diff --git a/common/locales/en/api-v3.json b/common/locales/en/api-v3.json
index c87946e717..d7239af5c4 100644
--- a/common/locales/en/api-v3.json
+++ b/common/locales/en/api-v3.json
@@ -38,6 +38,7 @@
   "memberCannotRemoveYourself": "You cannot remove yourself!",
   "groupMemberNotFound": "User not found among group's members",
   "keepOrRemoveAll": "req.query.keep must be either \"keep-all\" or \"remove-all\"",
+  "keepOrRemove": "req.query.keep must be either \"keep\" or \"remove\"",
   "canOnlyInviteEmailUuid": "Can only invite using uuids or emails.",
   "inviteMissingEmail": "Missing email address in invite.",
   "onlyGroupLeaderChal": "Only the group leader can create challenges",
@@ -48,6 +49,10 @@
   "challengeNotFound": "Challenge not found.",
   "onlyLeaderDeleteChal": "Only the challenge leader can delete it.",
   "winnerNotFound": "Winner with id \"<%= userId %>\" not found or not part of the challenge.",
+  "noCompletedTodosChallenge": "\"includeComepletedTodos\" is not supported when fetching a challenge tasks.",
+  "userTasksNoChallengeId": "When \"tasksOwner\" is \"user\" \"challengeId\" can't be passed.",
+  "onlyChalLeaderEditTasks": "Tasks belonging to a challenge can only be edited by the leader.",
+  "invalidTasksOwner": "\"tasksOwner\" must be \"user\" or \"challenge\".",
   "partyMustbePrivate": "Parties must be private",
   "userAlreadyInGroup": "User already in that group.",
   "userAlreadyInvitedToGroup": "User already invited to that group.",
@@ -56,5 +61,6 @@
   "userWithIDNotFound": "User with id \"<%= userId %>\" not found.",
   "uuidsMustBeAnArray": "UUIDs invites must be a an Array.",
   "emailsMustBeAnArray": "Email invites must be a an Array.",
-  "canOnlyInviteMaxInvites": "You can only invite \"<%= maxInvites %>\" at a time"
+  "canOnlyInviteMaxInvites": "You can only invite \"<%= maxInvites %>\" at a time",
+  "cantOnlyUnlinkChalTask": "Only challenges tasks can be unlinked."
 }
diff --git a/common/script/api-v3/cron.js b/common/script/api-v3/cron.js
index 604b6254f4..6f8626c7d8 100644
--- a/common/script/api-v3/cron.js
+++ b/common/script/api-v3/cron.js
@@ -1,7 +1,7 @@
 import moment from 'moment';
 import _ from 'lodash';
 import scoreTask from './scoreTask';
-import preenUserHistory from './preenHistory';
+import { preenUserHistory } from './preening';
 import common from '../../';
 import {
   shouldDo,
@@ -65,7 +65,7 @@ export default function cron (options = {}) {
         gemCapExtra: 0,
       });
 
-      user.markModified('purchased.plan'); // TODO necessary?
+      user.markModified('purchased.plan');
     }
   }
 
@@ -197,7 +197,7 @@ export default function cron (options = {}) {
   // preen user history so that it doesn't become a performance problem
   // also for subscribed users but differentyly
   // premium subscribers can keep their full history.
-  preenUserHistory(user, tasksByType);
+  preenUserHistory(user, tasksByType, user.preferences.timezoneOffset);
 
   if (perfect) {
     user.achievements.perfect++;
diff --git a/common/script/api-v3/preenHistory.js b/common/script/api-v3/preenHistory.js
deleted file mode 100644
index 64ae4e4715..0000000000
--- a/common/script/api-v3/preenHistory.js
+++ /dev/null
@@ -1,81 +0,0 @@
-import moment from 'moment';
-import _ from 'lodash';
-
-function _preen (newHistory, history, amount, groupBy) {
-  _.chain(history)
-    .groupBy(h => moment(h.date).format(groupBy))
-    .sortBy((h, k) => k)
-    .slice(-amount)
-    .pop()
-    .each((group) => {
-      newHistory.push({
-        date: moment(group[0].date).toDate(),
-        value: _.reduce(group, (m, obj) => m + obj.value, 0) / group.length,
-      });
-    })
-    .value();
-}
-
-// Free users:
-//  Preen history for users with > 7 history entries
-//  This takes an infinite array of single day entries [day day day day day...], and turns it into a condensed array
-//  of averages, condensing more the further back in time we go. Eg, 7 entries each for last 7 days; 1 entry each week
-//  of this month; 1 entry for each month of this year; 1 entry per previous year: [day*7 week*4 month*12 year*infinite]
-//
-// Subscribers:
-//  TODO implement
-
-// TODO Probably the description ^ is not too correct, this method actually takes 1 value each for the last 50 years,
-// then the X last months, where X is the month we're in (september = 8 starting from 0)
-// and all the days in this month
-// Allowing for multiple values in a single day for habits we probably want something different:
-// For free users:
-// - At max 30 values for today (max 30)
-// - 1 value each for the previous 61 days (2 months)
-// - 1 value each for the previous 10 months (max 10)
-// - 1 value each for the previous 50 years
-// - Total: 30+61+10+ a few years ~= 105
-//
-// For subscribed users
-// - At max 30 values for today (max 30)
-// - 1 value each for the previous 364 days (max 364)
-// - 1 value each for the previous 12 months (max 12)
-// - 1 value each for the previous 50 years
-// - Total: 30+364+12+ a few years ~= 410
-//
-export function preenHistory (history) {
-  // TODO remember to add this to migration
-  /* history = _.filter(history, function(h) {
-    return !!h;
-  }); */
-  let newHistory = [];
-
-  _preen(newHistory, history, 50, 'YYYY');
-  _preen(newHistory, history, moment().format('MM'), 'YYYYMM');
-
-  let thisMonth = moment().format('YYYYMM');
-  newHistory = newHistory.concat(history.filter(h => {
-    return moment(h.date).format('YYYYMM') === thisMonth;
-  }));
-
-  return newHistory;
-}
-
-export function preenUserHistory (user, tasksByType, minHistLen = 7) {
-  tasksByType.habits.concat(tasksByType.dailys).forEach((task) => {
-    if (task.history.length > minHistLen) {
-      task.history = preenHistory(user, task.history);
-      task.markModified('history');
-    }
-  });
-
-  if (user.history.exp.length > minHistLen) {
-    user.history.exp = preenHistory(user, user.history.exp);
-    user.markModified('history.exp');
-  }
-
-  if (user.history.todos.length > minHistLen) {
-    user.history.todos = preenHistory(user, user.history.todos);
-    user.markModified('history.todos');
-  }
-}
diff --git a/common/script/api-v3/preening.js b/common/script/api-v3/preening.js
new file mode 100644
index 0000000000..ee6a201b3a
--- /dev/null
+++ b/common/script/api-v3/preening.js
@@ -0,0 +1,82 @@
+import _ from 'lodash';
+import moment from 'moment';
+
+// Aggregate entries
+function _aggregate (history, aggregateBy) {
+  return _.chain(history)
+    .groupBy(entry => { // group entries by aggregateBy
+      return moment(entry.date).format(aggregateBy);
+    })
+    .sortBy((entry, key) => key) // sort by date
+    .map(entries => {
+      return {
+        date: Number(entries[0].date),
+        value: _.reduce(entries, (previousValue, entry) => {
+          return previousValue + entry.value;
+        }, 0) / entries.length,
+      };
+    })
+    .value();
+}
+
+/* Preen an array of history entries
+Free users:
+- 1 value for each day of the past 60 days (no compression)
+- 1 value each month for the previous 10 months
+- 1 value each year for the previous years
+Subscribers and challenges:
+- 1 value for each day of the past 365 days (no compression)
+- 1 value each month for the previous 12 months
+- 1 value each year for the previous years
+ */
+export function preenHistory (history, isSubscribed, timezoneOffset) {
+  // history = _.filter(history, historyEntry => Boolean(historyEntry)); // Filter missing entries TODO add to migration
+  let now = timezoneOffset ? moment().zone(timezoneOffset) : moment();
+  // Date after which to begin compressing data
+  let cutOff = now.subtract(isSubscribed ? 365 : 60, 'days').startOf('day');
+
+  // Keep uncompressed entries (modifies history)
+  let newHistory = _.remove(history, entry => {
+    let date = moment(entry.date);
+    return date.isSame(cutOff) || date.isAfter(cutOff);
+  });
+
+  // Date after which to begin compressing data by year
+  let monthsCutOff = cutOff.subtract(isSubscribed ? 12 : 10, 'months').startOf('day');
+  let aggregateByMonth = _.remove(history, entry => {
+    let date = moment(entry.date);
+    return date.isSame(monthsCutOff) || date.isAfter(monthsCutOff);
+  });
+  // Aggregate remaining entries by month and year
+  if (aggregateByMonth.length > 0) newHistory.unshift(..._aggregate(aggregateByMonth, 'YYYYMM'));
+  if (history.length > 0) newHistory.unshift(..._aggregate(history, 'YYYY'));
+
+  return newHistory;
+}
+
+// Preen history for users and tasks. This code runs only on the server.
+export function preenUserHistory (user, tasksByType) {
+  let isSubscribed = user.isSubscribed();
+  let timezoneOffset = user.preferences.timezoneOffset;
+  let minHistoryLength = isSubscribed ? 365 : 60;
+
+  function _processTask (task) {
+    if (task.history && task.history.length > minHistoryLength) {
+      task.history = preenHistory(task.history, isSubscribed, timezoneOffset);
+      task.markModified('history');
+    }
+  }
+
+  tasksByType.habits.forEach(_processTask);
+  tasksByType.dailys.forEach(_processTask);
+
+  if (user.history.exp.length > minHistoryLength) {
+    user.history.exp = preenHistory(user.history.exp, isSubscribed, timezoneOffset);
+    user.markModified('history.exp');
+  }
+
+  if (user.history.todos.length > minHistoryLength) {
+    user.history.todos = preenHistory(user.history.todos, isSubscribed, timezoneOffset);
+    user.markModified('history.todos');
+  }
+}
diff --git a/test/api/v3/integration/chat/GET-chat.test.js b/test/api/v3/integration/chat/GET-chat.test.js
index cb1e0996e6..dbd631e362 100644
--- a/test/api/v3/integration/chat/GET-chat.test.js
+++ b/test/api/v3/integration/chat/GET-chat.test.js
@@ -2,7 +2,7 @@ import {
   generateUser,
   generateGroup,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('GET /groups/:groupId/chat', () => {
   let user;
diff --git a/test/api/v3/integration/chat/POST-chat.flag.test.js b/test/api/v3/integration/chat/POST-chat.flag.test.js
index b71d462e5a..47ba58b046 100644
--- a/test/api/v3/integration/chat/POST-chat.flag.test.js
+++ b/test/api/v3/integration/chat/POST-chat.flag.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 import { find } from 'lodash';
 
 describe('POST /chat/:chatId/flag', () => {
diff --git a/test/api/v3/integration/chat/POST-chat.like.test.js b/test/api/v3/integration/chat/POST-chat.like.test.js
index 05d40f6e9f..cf266431ba 100644
--- a/test/api/v3/integration/chat/POST-chat.like.test.js
+++ b/test/api/v3/integration/chat/POST-chat.like.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 import { find } from 'lodash';
 
 describe('POST /chat/:chatId/like', () => {
diff --git a/test/api/v3/integration/chat/POST-chat.test.js b/test/api/v3/integration/chat/POST-chat.test.js
index 37403ed12d..fe943bfb1c 100644
--- a/test/api/v3/integration/chat/POST-chat.test.js
+++ b/test/api/v3/integration/chat/POST-chat.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('POST /chat', () => {
   let user;
diff --git a/test/api/v3/integration/groups/POST-groups.test.js b/test/api/v3/integration/groups/POST-groups.test.js
index 3515f07cec..8a64ef4bb5 100644
--- a/test/api/v3/integration/groups/POST-groups.test.js
+++ b/test/api/v3/integration/groups/POST-groups.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('POST /group', () => {
   let user;
diff --git a/test/api/v3/integration/groups/POST-groups_groupId_join.js b/test/api/v3/integration/groups/POST-groups_groupId_join.js
index 2c36d12f19..b35409bb6c 100644
--- a/test/api/v3/integration/groups/POST-groups_groupId_join.js
+++ b/test/api/v3/integration/groups/POST-groups_groupId_join.js
@@ -1,7 +1,8 @@
 import {
   generateUser,
+  createAndPopulateGroup,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('POST /group/:groupId/join', () => {
@@ -15,22 +16,28 @@ describe('POST /group/:groupId/join', () => {
     });
   });
 
-  context('Accepting invitation to a guild', () => {
+  context('Accepting invitation to a private guild', () => {
     let user, invitedUser, guild;
 
     beforeEach(async () => {
-      user = await generateUser({balance: 1});
-      guild = await user.post('/groups', {
-        name: 'Test Guild',
-        type: 'guild',
-        privacy: 'private',
+      let { group, groupLeader, invitees } = await createAndPopulateGroup({
+        groupDetails: {
+          name: 'Test Guild',
+          type: 'guild',
+          privacy: 'private',
+        },
+        invites: 1,
       });
+
+      guild = group;
+      user = groupLeader;
+      invitedUser = invitees[0];
     });
 
     it('returns error when user is not invited to private guild', async () => {
-      let joiningUser = await generateUser();
+      let userWithoutInvite = await generateUser();
 
-      await expect(joiningUser.post(`/groups/${guild._id}/join`)).to.eventually.be.rejected.and.eql({
+      await expect(userWithoutInvite.post(`/groups/${guild._id}/join`)).to.eventually.be.rejected.and.eql({
         code: 401,
         error: 'NotAuthorized',
         message: t('messageGroupRequiresInvite'),
@@ -38,26 +45,21 @@ describe('POST /group/:groupId/join', () => {
     });
 
     it('allows non-invited users to join public guilds', async () => {
-      await user.update({balance: 1});
-      guild = await user.post('/groups', {
-        name: 'Test Guild',
-        type: 'guild',
-        privacy: 'public',
-      });
+      let publicGuild = (await createAndPopulateGroup({
+        groupDetails: {
+          name: 'Test Guild',
+          type: 'guild',
+          privacy: 'public',
+        },
+      })).group;
 
       let joiningUser = await generateUser();
-      await joiningUser.post(`/groups/${guild._id}/join`);
+      await joiningUser.post(`/groups/${publicGuild._id}/join`);
 
-      await expect(joiningUser.get('/user')).to.eventually.have.property('guilds').to.include(guild._id);
+      await expect(joiningUser.get('/user')).to.eventually.have.property('guilds').and.to.include(publicGuild._id);
     });
 
     context('User is invited', () => {
-      beforeEach(async () => {
-        invitedUser = await generateUser({
-          'invitations.guilds': [{ id: guild._id}],
-        });
-      });
-
       it('allows invited user to join private guilds', async () => {
         await invitedUser.post(`/groups/${guild._id}/join`);
 
@@ -92,17 +94,23 @@ describe('POST /group/:groupId/join', () => {
     let user, invitedUser, party;
 
     beforeEach(async () => {
-      user = await generateUser();
-      party = await user.post('/groups', {
-        name: 'Test Party',
-        type: 'party',
+      let { group, groupLeader, invitees } = await createAndPopulateGroup({
+        groupDetails: {
+          name: 'Test Party',
+          type: 'party',
+        },
+        invites: 1,
       });
+
+      party = group;
+      user = groupLeader;
+      invitedUser = invitees[0];
     });
 
     it('returns error when user is not invited to party', async () => {
-      let joiningUser = await generateUser();
+      let userWithoutInvite = await generateUser();
 
-      await expect(joiningUser.post(`/groups/${party._id}/join`)).to.eventually.be.rejected.and.eql({
+      await expect(userWithoutInvite.post(`/groups/${party._id}/join`)).to.eventually.be.rejected.and.eql({
         code: 401,
         error: 'NotAuthorized',
         message: t('messageGroupRequiresInvite'),
@@ -110,12 +118,6 @@ describe('POST /group/:groupId/join', () => {
     });
 
     context('User is invited', () => {
-      beforeEach(async () => {
-        invitedUser = await generateUser({
-          'invitations.party': { id: party._id, inviter: user._id },
-        });
-      });
-
       it('allows invited user to join party', async () => {
         await invitedUser.post(`/groups/${party._id}/join`);
 
diff --git a/test/api/v3/integration/groups/POST-groups_invite.test.js b/test/api/v3/integration/groups/POST-groups_invite.test.js
index 2466bdf649..42719c0fcd 100644
--- a/test/api/v3/integration/groups/POST-groups_invite.test.js
+++ b/test/api/v3/integration/groups/POST-groups_invite.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 const INVITES_LIMIT = 100;
diff --git a/test/api/v3/integration/groups/PUT-groups.test.js b/test/api/v3/integration/groups/PUT-groups.test.js
index 6700374697..414f495ff7 100644
--- a/test/api/v3/integration/groups/PUT-groups.test.js
+++ b/test/api/v3/integration/groups/PUT-groups.test.js
@@ -1,32 +1,31 @@
 import {
-  generateUser,
+  createAndPopulateGroup,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('PUT /group', () => {
-  let groupLeader;
+  let leader, nonLeader, groupToUpdate;
   let groupName = 'Test Public Guild';
   let groupType = 'guild';
-  let groupToUpdate;
   let groupUpdatedName = 'Test Public Guild Updated';
 
   beforeEach(async () => {
-    groupLeader = await generateUser({balance: 1});
-    groupToUpdate = await groupLeader.post('/groups', {
-      name: groupName,
-      type: groupType,
+    let { group, groupLeader, members } = await createAndPopulateGroup({
+      groupDetails: {
+        name: groupName,
+        type: groupType,
+        privacy: 'public',
+      },
+      members: 1,
     });
+
+    groupToUpdate = group;
+    leader = groupLeader;
+    nonLeader = members[0];
   });
 
   it('returns an error when a non group leader tries to update', async () => {
-    let memberToAttemptUpdate = await generateUser();
-
-    await groupLeader.post(`/groups/${groupToUpdate._id}/invite`, {
-      uuids: [memberToAttemptUpdate._id],
-    });
-    await memberToAttemptUpdate.post(`/groups/${groupToUpdate._id}/join`);
-
-    await expect(memberToAttemptUpdate.put(`/groups/${groupToUpdate._id}`, {
+    await expect(nonLeader.put(`/groups/${groupToUpdate._id}`, {
       name: groupUpdatedName,
     })).to.eventually.be.rejected.and.eql({
       code: 401,
@@ -36,7 +35,7 @@ describe('PUT /group', () => {
   });
 
   it('updates a group', async () => {
-    let updatedGroup = await groupLeader.put(`/groups/${groupToUpdate._id}`, {
+    let updatedGroup = await leader.put(`/groups/${groupToUpdate._id}`, {
       name: groupUpdatedName,
     });
 
diff --git a/test/api/v3/integration/notFound.test.js b/test/api/v3/integration/notFound.test.js
index 6539a0037d..959e0d8b28 100644
--- a/test/api/v3/integration/notFound.test.js
+++ b/test/api/v3/integration/notFound.test.js
@@ -1,4 +1,4 @@
-import { requester } from '../../../helpers/api-integration.helper';
+import { requester } from '../../../helpers/api-v3-integration.helper';
 
 describe('notFound Middleware', () => {
   it('returns a 404 error when the resource is not found', async () => {
diff --git a/test/api/v3/integration/tags/DELETE-tags_id.test.js b/test/api/v3/integration/tags/DELETE-tags_id.test.js
index 9d6b53c531..3aefe11d48 100644
--- a/test/api/v3/integration/tags/DELETE-tags_id.test.js
+++ b/test/api/v3/integration/tags/DELETE-tags_id.test.js
@@ -1,6 +1,6 @@
 import {
   generateUser,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('DELETE /tags/:tagId', () => {
   let user;
diff --git a/test/api/v3/integration/tags/GET-tags.test.js b/test/api/v3/integration/tags/GET-tags.test.js
index 5281bd35af..6c27da12c3 100644
--- a/test/api/v3/integration/tags/GET-tags.test.js
+++ b/test/api/v3/integration/tags/GET-tags.test.js
@@ -1,6 +1,6 @@
 import {
   generateUser,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('GET /tags', () => {
   let user;
diff --git a/test/api/v3/integration/tags/GET-tags_id.test.js b/test/api/v3/integration/tags/GET-tags_id.test.js
index adccff6504..1189c2af24 100644
--- a/test/api/v3/integration/tags/GET-tags_id.test.js
+++ b/test/api/v3/integration/tags/GET-tags_id.test.js
@@ -1,6 +1,6 @@
 import {
   generateUser,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('GET /tags/:tagId', () => {
   let user;
diff --git a/test/api/v3/integration/tags/POST-tags.test.js b/test/api/v3/integration/tags/POST-tags.test.js
index 7b7b5c4a34..85947e5add 100644
--- a/test/api/v3/integration/tags/POST-tags.test.js
+++ b/test/api/v3/integration/tags/POST-tags.test.js
@@ -1,6 +1,6 @@
 import {
   generateUser,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('POST /tags', () => {
   let user;
diff --git a/test/api/v3/integration/tags/PUT-tags_id.test.js b/test/api/v3/integration/tags/PUT-tags_id.test.js
index c2576a3f0c..4653f284d6 100644
--- a/test/api/v3/integration/tags/PUT-tags_id.test.js
+++ b/test/api/v3/integration/tags/PUT-tags_id.test.js
@@ -1,6 +1,6 @@
 import {
   generateUser,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('PUT /tags/:tagId', () => {
   let user;
diff --git a/test/api/v3/integration/tasks/DELETE-tasks_id.test.js b/test/api/v3/integration/tasks/DELETE-tasks_id.test.js
index 59866dab3b..cd0884ddbb 100644
--- a/test/api/v3/integration/tasks/DELETE-tasks_id.test.js
+++ b/test/api/v3/integration/tasks/DELETE-tasks_id.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('DELETE /tasks/:id', () => {
   let user;
@@ -14,7 +14,7 @@ describe('DELETE /tasks/:id', () => {
     let task;
 
     beforeEach(async () => {
-      task = await user.post('/tasks', {
+      task = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
       });
@@ -42,7 +42,7 @@ describe('DELETE /tasks/:id', () => {
 
     it('cannot delete a task owned by someone else', async () => {
       let anotherUser = await generateUser();
-      let anotherUsersTask = await anotherUser.post('/tasks', {
+      let anotherUsersTask = await anotherUser.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
       });
diff --git a/test/api/v3/integration/tasks/GET-tasks.test.js b/test/api/v3/integration/tasks/GET-tasks.test.js
deleted file mode 100644
index 4c169b3f6c..0000000000
--- a/test/api/v3/integration/tasks/GET-tasks.test.js
+++ /dev/null
@@ -1,34 +0,0 @@
-import {
-  generateUser,
-} from '../../../../helpers/api-integration.helper';
-import Q from 'q';
-
-describe('GET /tasks', () => {
-  let user;
-
-  beforeEach(async () => {
-    user = await generateUser();
-  });
-
-  it('returns all user\'s tasks', async () => {
-    let createdTasks = await Q.all([
-      user.post('/tasks', {text: 'test habit', type: 'habit'}),
-    ]);
-
-    let length = createdTasks.length;
-    let tasks = await user.get('/tasks');
-
-    expect(tasks.length).to.equal(length + 1); // + 1 because 1 is a default task
-  });
-
-  it('returns only a type of user\'s tasks if req.query.type is specified', async () => {
-    let task = await user.post('/tasks', {text: 'test habit', type: 'habit'});
-    let tasks = await user.get('/tasks?type=habit');
-
-    expect(tasks.length).to.equal(1);
-    expect(tasks[0]._id).to.equal(task._id);
-  });
-
-  // TODO complete after task scoring is done
-  it('returns completed todos sorted by creation date if req.query.includeCompletedTodos is specified');
-});
diff --git a/test/api/v3/integration/tasks/GET-tasks_id.test.js b/test/api/v3/integration/tasks/GET-tasks_id.test.js
index 84df18187a..1e61feaa7b 100644
--- a/test/api/v3/integration/tasks/GET-tasks_id.test.js
+++ b/test/api/v3/integration/tasks/GET-tasks_id.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('GET /tasks/:id', () => {
@@ -15,7 +15,7 @@ describe('GET /tasks/:id', () => {
     let task;
 
     beforeEach(async () => {
-      task = await user.post('/tasks', {
+      task = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
       });
@@ -43,7 +43,7 @@ describe('GET /tasks/:id', () => {
 
     it('cannot get a task owned by someone else', async () => {
       let anotherUser = await generateUser();
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
       });
diff --git a/test/api/v3/integration/tasks/GET-tasks_user.test.js b/test/api/v3/integration/tasks/GET-tasks_user.test.js
new file mode 100644
index 0000000000..6c4d4f5b30
--- /dev/null
+++ b/test/api/v3/integration/tasks/GET-tasks_user.test.js
@@ -0,0 +1,27 @@
+import {
+  generateUser,
+} from '../../../../helpers/api-integration.helper';
+
+describe('GET /tasks/user', () => {
+  let user;
+
+  beforeEach(async () => {
+    user = await generateUser();
+  });
+
+  it('returns all user\'s tasks', async () => {
+    let createdTasks = await user.post('/tasks/user', [{text: 'test habit', type: 'habit'}, {text: 'test todo', type: 'todo'}]);
+    let tasks = await user.get('/tasks/user');
+    expect(tasks.length).to.equal(createdTasks.length + 1); // + 1 because 1 is a default task
+  });
+
+  it('returns only a type of user\'s tasks if req.query.type is specified', async () => {
+    let createdTasks = await user.post('/tasks/user', [{text: 'test habit', type: 'habit'}, {text: 'test todo', type: 'todo'}]);
+    let tasks = await user.get('/tasks/user?type=habit');
+    expect(tasks.length).to.equal(1);
+    expect(tasks[0]._id).to.equal(createdTasks[0]._id);
+  });
+
+  // TODO complete after task scoring is done
+  it('returns completed todos sorted by creation date if req.query.includeCompletedTodos is specified');
+});
diff --git a/test/api/v3/integration/tasks/POST-tasks_id_score_direction.test.js b/test/api/v3/integration/tasks/POST-tasks_id_score_direction.test.js
index b01a54775c..fab83738f5 100644
--- a/test/api/v3/integration/tasks/POST-tasks_id_score_direction.test.js
+++ b/test/api/v3/integration/tasks/POST-tasks_id_score_direction.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('POST /tasks/:id/score/:direction', () => {
@@ -35,7 +35,7 @@ describe('POST /tasks/:id/score/:direction', () => {
     let todo;
 
     beforeEach(async () => {
-      todo = await user.post('/tasks', {
+      todo = await user.post('/tasks/user', {
         text: 'test todo',
         type: 'todo',
       });
@@ -134,7 +134,7 @@ describe('POST /tasks/:id/score/:direction', () => {
     let daily;
 
     beforeEach(async () => {
-      daily = await user.post('/tasks', {
+      daily = await user.post('/tasks/user', {
         text: 'test daily',
         type: 'daily',
       });
@@ -205,24 +205,24 @@ describe('POST /tasks/:id/score/:direction', () => {
     let habit, minusHabit, plusHabit, neitherHabit; // eslint-disable-line no-unused-vars
 
     beforeEach(async () => {
-      habit = await user.post('/tasks', {
+      habit = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
       });
 
-      minusHabit = await user.post('/tasks', {
+      minusHabit = await user.post('/tasks/user', {
         text: 'test min habit',
         type: 'habit',
         up: false,
       });
 
-      plusHabit = await user.post('/tasks', {
+      plusHabit = await user.post('/tasks/user', {
         text: 'test plus habit',
         type: 'habit',
         down: false,
       });
 
-      neitherHabit = await user.post('/tasks', {
+      neitherHabit = await user.post('/tasks/user', {
         text: 'test neither habit',
         type: 'habit',
         up: false,
@@ -267,7 +267,7 @@ describe('POST /tasks/:id/score/:direction', () => {
     let reward, updatedUser;
 
     beforeEach(async () => {
-      reward = await user.post('/tasks', {
+      reward = await user.post('/tasks/user', {
         text: 'test reward',
         type: 'reward',
         value: 5,
diff --git a/test/api/v3/integration/tasks/POST-tasks.test.js b/test/api/v3/integration/tasks/POST-tasks_user.test.js
similarity index 87%
rename from test/api/v3/integration/tasks/POST-tasks.test.js
rename to test/api/v3/integration/tasks/POST-tasks_user.test.js
index 7ce45a9d71..906bc8feed 100644
--- a/test/api/v3/integration/tasks/POST-tasks.test.js
+++ b/test/api/v3/integration/tasks/POST-tasks_user.test.js
@@ -1,9 +1,9 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
-describe('POST /tasks', () => {
+describe('POST /tasks/user', () => {
   let user;
 
   before(async () => {
@@ -12,7 +12,7 @@ describe('POST /tasks', () => {
 
   context('validates params', async () => {
     it('returns an error if req.body.type is absent', async () => {
-      await expect(user.post('/tasks', {
+      await expect(user.post('/tasks/user', {
         notType: 'habit',
       })).to.eventually.be.rejected.and.eql({
         code: 400,
@@ -22,7 +22,7 @@ describe('POST /tasks', () => {
     });
 
     it('returns an error if req.body.type is not valid', async () => {
-      await expect(user.post('/tasks', {
+      await expect(user.post('/tasks/user', {
         type: 'habitF',
       })).to.eventually.be.rejected.and.eql({
         code: 400,
@@ -32,7 +32,7 @@ describe('POST /tasks', () => {
     });
 
     it('returns an error if one object inside an array is invalid', async () => {
-      await expect(user.post('/tasks', [
+      await expect(user.post('/tasks/user', [
         {type: 'habitF'},
         {type: 'habit'},
       ])).to.eventually.be.rejected.and.eql({
@@ -43,7 +43,7 @@ describe('POST /tasks', () => {
     });
 
     it('returns an error if req.body.text is absent', async () => {
-      await expect(user.post('/tasks', {
+      await expect(user.post('/tasks/user', {
         type: 'habit',
       })).to.eventually.be.rejected.and.eql({
         code: 400,
@@ -54,7 +54,7 @@ describe('POST /tasks', () => {
 
     it('does not update user.tasksOrder.{taskType} when the task is not saved because invalid', async () => {
       let originalHabitsOrder = (await user.get('/user')).tasksOrder.habits;
-      await expect(user.post('/tasks', {
+      await expect(user.post('/tasks/user', {
         type: 'habit',
       })).to.eventually.be.rejected.and.eql({ // this block is necessary
         code: 400,
@@ -68,7 +68,7 @@ describe('POST /tasks', () => {
 
     it('does not update user.tasksOrder.{taskType} when a task inside an array is not saved because invalid', async () => {
       let originalHabitsOrder = (await user.get('/user')).tasksOrder.habits;
-      await expect(user.post('/tasks', [
+      await expect(user.post('/tasks/user', [
         {type: 'habit'}, // Missing text
         {type: 'habit', text: 'valid'}, // Valid
       ])).to.eventually.be.rejected.and.eql({ // this block is necessary
@@ -82,14 +82,18 @@ describe('POST /tasks', () => {
     });
 
     it('does not save any task sent in an array when 1 is invalid', async () => {
-      let originalTasks = await user.get('/tasks');
-      await expect(user.post('/tasks', [
+      let originalTasks = await user.get('/tasks/user');
+      await expect(user.post('/tasks/user', [
         {type: 'habit'}, // Missing text
         {type: 'habit', text: 'valid'}, // Valid
       ])).to.eventually.be.rejected.and.eql({ // this block is necessary
         code: 400,
         error: 'BadRequest',
         message: 'habit validation failed',
+      }).then(async () => {
+        let updatedTasks = await user.get('/tasks/user');
+
+        expect(updatedTasks).to.eql(originalTasks);
       });
 
       let updatedTasks = await user.get('/tasks');
@@ -97,7 +101,7 @@ describe('POST /tasks', () => {
     });
 
     it('automatically sets "task.userId" to user\'s uuid', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
       });
@@ -108,7 +112,7 @@ describe('POST /tasks', () => {
     it(`ignores setting userId, history, createdAt,
                         updatedAt, challenge, completed, streak,
                         dateCompleted fields`, async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test daily',
         type: 'daily',
         userId: 123,
@@ -132,7 +136,7 @@ describe('POST /tasks', () => {
     });
 
     it('ignores invalid fields', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test daily',
         type: 'daily',
         notValid: true,
@@ -144,7 +148,7 @@ describe('POST /tasks', () => {
 
   context('habits', () => {
     it('creates a habit', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
         up: false,
@@ -162,7 +166,7 @@ describe('POST /tasks', () => {
 
     it('updates user.tasksOrder.habits when a new habit is created', async () => {
       let originalHabitsOrderLen = (await user.get('/user')).tasksOrder.habits.length;
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         type: 'habit',
         text: 'an habit',
       });
@@ -174,7 +178,7 @@ describe('POST /tasks', () => {
 
     it('updates user.tasksOrder.habits when multiple habits are created', async () => {
       let originalHabitsOrderLen = (await user.get('/user')).tasksOrder.habits.length;
-      let [task, task2] = await user.post('/tasks', [{
+      let [task, task2] = await user.post('/tasks/user', [{
         type: 'habit',
         text: 'an habit',
       }, {
@@ -189,7 +193,7 @@ describe('POST /tasks', () => {
     });
 
     it('creates multiple habits', async () => {
-      let [task, task2] = await user.post('/tasks', [{
+      let [task, task2] = await user.post('/tasks/user', [{
         text: 'test habit',
         type: 'habit',
         up: false,
@@ -219,7 +223,7 @@ describe('POST /tasks', () => {
     });
 
     it('defaults to setting up and down to true', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
         notes: 1976,
@@ -230,7 +234,7 @@ describe('POST /tasks', () => {
     });
 
     it('cannot create checklists', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
         checklist: [
@@ -244,7 +248,7 @@ describe('POST /tasks', () => {
 
   context('todos', () => {
     it('creates a todo', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test todo',
         type: 'todo',
         notes: 1976,
@@ -257,7 +261,7 @@ describe('POST /tasks', () => {
     });
 
     it('creates multiple todos', async () => {
-      let [task, task2] = await user.post('/tasks', [{
+      let [task, task2] = await user.post('/tasks/user', [{
         text: 'test todo',
         type: 'todo',
         notes: 1976,
@@ -280,7 +284,7 @@ describe('POST /tasks', () => {
 
     it('updates user.tasksOrder.todos when a new todo is created', async () => {
       let originalTodosOrderLen = (await user.get('/user')).tasksOrder.todos.length;
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         type: 'todo',
         text: 'a todo',
       });
@@ -292,7 +296,7 @@ describe('POST /tasks', () => {
 
     it('updates user.tasksOrder.todos when multiple todos are created', async () => {
       let originalTodosOrderLen = (await user.get('/user')).tasksOrder.todos.length;
-      let [task, task2] = await user.post('/tasks', [{
+      let [task, task2] = await user.post('/tasks/user', [{
         type: 'todo',
         text: 'a todo',
       }, {
@@ -307,7 +311,7 @@ describe('POST /tasks', () => {
     });
 
     it('can create checklists', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test todo',
         type: 'todo',
         checklist: [
@@ -328,7 +332,7 @@ describe('POST /tasks', () => {
     it('creates a daily', async () => {
       let now = new Date();
 
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test daily',
         type: 'daily',
         notes: 1976,
@@ -347,7 +351,7 @@ describe('POST /tasks', () => {
     });
 
     it('creates multiple dailys', async () => {
-      let [task, task2] = await user.post('/tasks', [{
+      let [task, task2] = await user.post('/tasks/user', [{
         text: 'test daily',
         type: 'daily',
         notes: 1976,
@@ -370,7 +374,7 @@ describe('POST /tasks', () => {
 
     it('updates user.tasksOrder.dailys when a new daily is created', async () => {
       let originalDailysOrderLen = (await user.get('/user')).tasksOrder.dailys.length;
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         type: 'daily',
         text: 'a daily',
       });
@@ -382,7 +386,7 @@ describe('POST /tasks', () => {
 
     it('updates user.tasksOrder.dailys when multiple dailys are created', async () => {
       let originalDailysOrderLen = (await user.get('/user')).tasksOrder.dailys.length;
-      let [task, task2] = await user.post('/tasks', [{
+      let [task, task2] = await user.post('/tasks/user', [{
         type: 'daily',
         text: 'a daily',
       }, {
@@ -397,7 +401,7 @@ describe('POST /tasks', () => {
     });
 
     it('defaults to a weekly frequency, with every day set', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test daily',
         type: 'daily',
       });
@@ -416,7 +420,7 @@ describe('POST /tasks', () => {
     });
 
     it('allows repeat field to be configured', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test daily',
         type: 'daily',
         repeat: {
@@ -440,7 +444,7 @@ describe('POST /tasks', () => {
     it('defaults startDate to today', async () => {
       let today = (new Date()).getDay();
 
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test daily',
         type: 'daily',
       });
@@ -449,7 +453,7 @@ describe('POST /tasks', () => {
     });
 
     it('can create checklists', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test daily',
         type: 'daily',
         checklist: [
@@ -468,7 +472,7 @@ describe('POST /tasks', () => {
 
   context('rewards', () => {
     it('creates a reward', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test reward',
         type: 'reward',
         notes: 1976,
@@ -483,7 +487,7 @@ describe('POST /tasks', () => {
     });
 
     it('creates multiple rewards', async () => {
-      let [task, task2] = await user.post('/tasks', [{
+      let [task, task2] = await user.post('/tasks/user', [{
         text: 'test reward',
         type: 'reward',
         notes: 1976,
@@ -510,7 +514,7 @@ describe('POST /tasks', () => {
 
     it('updates user.tasksOrder.rewards when a new reward is created', async () => {
       let originalRewardsOrderLen = (await user.get('/user')).tasksOrder.rewards.length;
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         type: 'reward',
         text: 'a reward',
       });
@@ -522,7 +526,7 @@ describe('POST /tasks', () => {
 
     it('updates user.tasksOrder.dreward when multiple rewards are created', async () => {
       let originalRewardsOrderLen = (await user.get('/user')).tasksOrder.rewards.length;
-      let [task, task2] = await user.post('/tasks', [{
+      let [task, task2] = await user.post('/tasks/user', [{
         type: 'reward',
         text: 'a reward',
       }, {
@@ -537,7 +541,7 @@ describe('POST /tasks', () => {
     });
 
     it('defaults to a 0 value', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test reward',
         type: 'reward',
       });
@@ -546,7 +550,7 @@ describe('POST /tasks', () => {
     });
 
     it('requires value to be coerced into a number', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test reward',
         type: 'reward',
         value: '10',
@@ -556,7 +560,7 @@ describe('POST /tasks', () => {
     });
 
     it('cannot create checklists', async () => {
-      let task = await user.post('/tasks', {
+      let task = await user.post('/tasks/user', {
         text: 'test reward',
         type: 'reward',
         checklist: [
diff --git a/test/api/v3/integration/tasks/PUT-tasks_id.test.js b/test/api/v3/integration/tasks/PUT-tasks_id.test.js
index bbb42fa69b..4751daf7c7 100644
--- a/test/api/v3/integration/tasks/PUT-tasks_id.test.js
+++ b/test/api/v3/integration/tasks/PUT-tasks_id.test.js
@@ -1,6 +1,6 @@
 import {
   generateUser,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('PUT /tasks/:id', () => {
@@ -14,7 +14,7 @@ describe('PUT /tasks/:id', () => {
     let task;
 
     beforeEach(async () => {
-      task = await user.post('/tasks', {
+      task = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
       });
@@ -61,7 +61,7 @@ describe('PUT /tasks/:id', () => {
     let habit;
 
     beforeEach(async () => {
-      habit = await user.post('/tasks', {
+      habit = await user.post('/tasks/user', {
         text: 'test habit',
         type: 'habit',
         notes: 1976,
@@ -87,7 +87,7 @@ describe('PUT /tasks/:id', () => {
     let todo;
 
     beforeEach(async () => {
-      todo = await user.post('/tasks', {
+      todo = await user.post('/tasks/user', {
         text: 'test todo',
         type: 'todo',
         notes: 1976,
@@ -142,7 +142,7 @@ describe('PUT /tasks/:id', () => {
     let daily;
 
     beforeEach(async () => {
-      daily = await user.post('/tasks', {
+      daily = await user.post('/tasks/user', {
         text: 'test daily',
         type: 'daily',
         notes: 1976,
@@ -244,7 +244,7 @@ describe('PUT /tasks/:id', () => {
     let reward;
 
     beforeEach(async () => {
-      reward = await user.post('/tasks', {
+      reward = await user.post('/tasks/user', {
         text: 'test reward',
         type: 'reward',
         notes: 1976,
diff --git a/test/api/v3/integration/tasks/checklists/DELETE-tasks_taskId_checklist_itemId.test.js b/test/api/v3/integration/tasks/checklists/DELETE-tasks_taskId_checklist_itemId.test.js
index 6c690c6eb9..cdd8cd09f5 100644
--- a/test/api/v3/integration/tasks/checklists/DELETE-tasks_taskId_checklist_itemId.test.js
+++ b/test/api/v3/integration/tasks/checklists/DELETE-tasks_taskId_checklist_itemId.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../../helpers/api-integration.helper';
+} from '../../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('DELETE /tasks/:taskId/checklist/:itemId', () => {
@@ -12,7 +12,7 @@ describe('DELETE /tasks/:taskId/checklist/:itemId', () => {
   });
 
   it('deletes a checklist item', async () => {
-    let task = await user.post('/tasks', {
+    let task = await user.post('/tasks/user', {
       type: 'daily',
       text: 'Daily with checklist',
     });
@@ -26,7 +26,7 @@ describe('DELETE /tasks/:taskId/checklist/:itemId', () => {
   });
 
   it('does not work with habits', async () => {
-    let habit = await user.post('/tasks', {
+    let habit = await user.post('/tasks/user', {
       type: 'habit',
       text: 'habit with checklist',
     });
@@ -39,7 +39,7 @@ describe('DELETE /tasks/:taskId/checklist/:itemId', () => {
   });
 
   it('does not work with rewards', async () => {
-    let reward = await user.post('/tasks', {
+    let reward = await user.post('/tasks/user', {
       type: 'reward',
       text: 'reward with checklist',
     });
@@ -60,7 +60,7 @@ describe('DELETE /tasks/:taskId/checklist/:itemId', () => {
   });
 
   it('fails on checklist item not found', async () => {
-    let createdTask = await user.post('/tasks', {
+    let createdTask = await user.post('/tasks/user', {
       type: 'daily',
       text: 'daily with checklist',
     });
diff --git a/test/api/v3/integration/tasks/checklists/POST-tasks_taskId_checklist.test.js b/test/api/v3/integration/tasks/checklists/POST-tasks_taskId_checklist.test.js
index 3e1dfb8494..d7f738007e 100644
--- a/test/api/v3/integration/tasks/checklists/POST-tasks_taskId_checklist.test.js
+++ b/test/api/v3/integration/tasks/checklists/POST-tasks_taskId_checklist.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../../helpers/api-integration.helper';
+} from '../../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('POST /tasks/:taskId/checklist/', () => {
@@ -12,7 +12,7 @@ describe('POST /tasks/:taskId/checklist/', () => {
   });
 
   it('adds a checklist item to a task', async () => {
-    let task = await user.post('/tasks', {
+    let task = await user.post('/tasks/user', {
       type: 'daily',
       text: 'Daily with checklist',
     });
@@ -32,7 +32,7 @@ describe('POST /tasks/:taskId/checklist/', () => {
   });
 
   it('does not add a checklist to habits', async () => {
-    let habit = await user.post('/tasks', {
+    let habit = await user.post('/tasks/user', {
       type: 'habit',
       text: 'habit with checklist',
     });
@@ -47,7 +47,7 @@ describe('POST /tasks/:taskId/checklist/', () => {
   });
 
   it('does not add a checklist to rewards', async () => {
-    let reward = await user.post('/tasks', {
+    let reward = await user.post('/tasks/user', {
       type: 'reward',
       text: 'reward with checklist',
     });
diff --git a/test/api/v3/integration/tasks/checklists/POST-tasks_taskId_checklist_itemId_score.test.js b/test/api/v3/integration/tasks/checklists/POST-tasks_taskId_checklist_itemId_score.test.js
index 345e1c400e..c91e365668 100644
--- a/test/api/v3/integration/tasks/checklists/POST-tasks_taskId_checklist_itemId_score.test.js
+++ b/test/api/v3/integration/tasks/checklists/POST-tasks_taskId_checklist_itemId_score.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../../helpers/api-integration.helper';
+} from '../../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('POST /tasks/:taskId/checklist/:itemId/score', () => {
@@ -12,7 +12,7 @@ describe('POST /tasks/:taskId/checklist/:itemId/score', () => {
   });
 
   it('scores a checklist item', async () => {
-    let task = await user.post('/tasks', {
+    let task = await user.post('/tasks/user', {
       type: 'daily',
       text: 'Daily with checklist',
     });
@@ -29,7 +29,7 @@ describe('POST /tasks/:taskId/checklist/:itemId/score', () => {
   });
 
   it('fails on habits', async () => {
-    let habit = await user.post('/tasks', {
+    let habit = await user.post('/tasks/user', {
       type: 'habit',
       text: 'habit with checklist',
     });
@@ -44,7 +44,7 @@ describe('POST /tasks/:taskId/checklist/:itemId/score', () => {
   });
 
   it('fails on rewards', async () => {
-    let reward = await user.post('/tasks', {
+    let reward = await user.post('/tasks/user', {
       type: 'reward',
       text: 'reward with checklist',
     });
@@ -65,7 +65,7 @@ describe('POST /tasks/:taskId/checklist/:itemId/score', () => {
   });
 
   it('fails on checklist item not found', async () => {
-    let createdTask = await user.post('/tasks', {
+    let createdTask = await user.post('/tasks/user', {
       type: 'daily',
       text: 'daily with checklist',
     });
diff --git a/test/api/v3/integration/tasks/checklists/PUT-tasks_taskId_checklist_itemId.test.js b/test/api/v3/integration/tasks/checklists/PUT-tasks_taskId_checklist_itemId.test.js
index 0d93f6cc64..a8d9c0536b 100644
--- a/test/api/v3/integration/tasks/checklists/PUT-tasks_taskId_checklist_itemId.test.js
+++ b/test/api/v3/integration/tasks/checklists/PUT-tasks_taskId_checklist_itemId.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../../helpers/api-integration.helper';
+} from '../../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('PUT /tasks/:taskId/checklist/:itemId', () => {
@@ -12,7 +12,7 @@ describe('PUT /tasks/:taskId/checklist/:itemId', () => {
   });
 
   it('updates a checklist item', async () => {
-    let task = await user.post('/tasks', {
+    let task = await user.post('/tasks/user', {
       type: 'daily',
       text: 'Daily with checklist',
     });
@@ -35,7 +35,7 @@ describe('PUT /tasks/:taskId/checklist/:itemId', () => {
   });
 
   it('fails on habits', async () => {
-    let habit = await user.post('/tasks', {
+    let habit = await user.post('/tasks/user', {
       type: 'habit',
       text: 'habit with checklist',
     });
@@ -48,7 +48,7 @@ describe('PUT /tasks/:taskId/checklist/:itemId', () => {
   });
 
   it('fails on rewards', async () => {
-    let reward = await user.post('/tasks', {
+    let reward = await user.post('/tasks/user', {
       type: 'reward',
       text: 'reward with checklist',
     });
@@ -69,7 +69,7 @@ describe('PUT /tasks/:taskId/checklist/:itemId', () => {
   });
 
   it('fails on checklist item not found', async () => {
-    let createdTask = await user.post('/tasks', {
+    let createdTask = await user.post('/tasks/user', {
       type: 'daily',
       text: 'daily with checklist',
     });
diff --git a/test/api/v3/integration/tasks/tags/DELETE-tasks_taskId_tags_tagId.test.js b/test/api/v3/integration/tasks/tags/DELETE-tasks_taskId_tags_tagId.test.js
index 7ddeb6fe14..02640f9879 100644
--- a/test/api/v3/integration/tasks/tags/DELETE-tasks_taskId_tags_tagId.test.js
+++ b/test/api/v3/integration/tasks/tags/DELETE-tasks_taskId_tags_tagId.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../../helpers/api-integration.helper';
+} from '../../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('DELETE /tasks/:taskId/tags/:tagId', () => {
@@ -12,7 +12,7 @@ describe('DELETE /tasks/:taskId/tags/:tagId', () => {
   });
 
   it('removes a tag from a task', async () => {
-    let task = await user.post('/tasks', {
+    let task = await user.post('/tasks/user', {
       type: 'habit',
       text: 'Task with tag',
     });
@@ -28,7 +28,7 @@ describe('DELETE /tasks/:taskId/tags/:tagId', () => {
   });
 
   it('only deletes existing tags', async () => {
-    let createdTask = await user.post('/tasks', {
+    let createdTask = await user.post('/tasks/user', {
       type: 'habit',
       text: 'Task with tag',
     });
diff --git a/test/api/v3/integration/tasks/tags/POST-tasks_taskId_tags_tagId.test.js b/test/api/v3/integration/tasks/tags/POST-tasks_taskId_tags_tagId.test.js
index 8377d5a012..93313b7a69 100644
--- a/test/api/v3/integration/tasks/tags/POST-tasks_taskId_tags_tagId.test.js
+++ b/test/api/v3/integration/tasks/tags/POST-tasks_taskId_tags_tagId.test.js
@@ -1,7 +1,7 @@
 import {
   generateUser,
   translate as t,
-} from '../../../../../helpers/api-integration.helper';
+} from '../../../../../helpers/api-v3-integration.helper';
 import { v4 as generateUUID } from 'uuid';
 
 describe('POST /tasks/:taskId/tags/:tagId', () => {
@@ -12,7 +12,7 @@ describe('POST /tasks/:taskId/tags/:tagId', () => {
   });
 
   it('adds a tag to a task', async () => {
-    let task = await user.post('/tasks', {
+    let task = await user.post('/tasks/user', {
       type: 'habit',
       text: 'Task with tag',
     });
@@ -24,7 +24,7 @@ describe('POST /tasks/:taskId/tags/:tagId', () => {
   });
 
   it('does not add a tag to a task twice', async () => {
-    let task = await user.post('/tasks', {
+    let task = await user.post('/tasks/user', {
       type: 'habit',
       text: 'Task with tag',
     });
@@ -41,7 +41,7 @@ describe('POST /tasks/:taskId/tags/:tagId', () => {
   });
 
   it('does not add a non existing tag to a task', async () => {
-    let task = await user.post('/tasks', {
+    let task = await user.post('/tasks/user', {
       type: 'habit',
       text: 'Task with tag',
     });
diff --git a/test/api/v3/integration/user/GET-user.test.js b/test/api/v3/integration/user/GET-user.test.js
index 8fbedca8cc..692c4c2ab9 100644
--- a/test/api/v3/integration/user/GET-user.test.js
+++ b/test/api/v3/integration/user/GET-user.test.js
@@ -1,6 +1,6 @@
 import {
   generateUser,
-} from '../../../../helpers/api-integration.helper';
+} from '../../../../helpers/api-v3-integration.helper';
 
 describe('GET /user', () => {
   let user;
diff --git a/test/api/v3/integration/user/auth/POST-register_local.test.js b/test/api/v3/integration/user/auth/POST-register_local.test.js
index 68ff003645..5255a31780 100644
--- a/test/api/v3/integration/user/auth/POST-register_local.test.js
+++ b/test/api/v3/integration/user/auth/POST-register_local.test.js
@@ -2,7 +2,7 @@ import {
   generateUser,
   requester,
   translate as t,
-} from '../../../../../helpers/api-integration.helper';
+} from '../../../../../helpers/api-v3-integration.helper';
 import { v4 as generateRandomUserName } from 'uuid';
 import { each } from 'lodash';
 
diff --git a/test/common/algos.mocha.js b/test/common/algos.mocha.js
index 8c18e3c92c..0528d62933 100644
--- a/test/common/algos.mocha.js
+++ b/test/common/algos.mocha.js
@@ -938,124 +938,6 @@ describe('Cron', () => {
     expect(beforeTasks).to.eql(afterTasks);
   });
 
-  describe('preening', () => {
-    beforeEach(function () {
-      this.clock = sinon.useFakeTimers(Date.parse('2013-11-20'), 'Date');
-    });
-    afterEach(function () {
-      return this.clock.restore();
-    });
-
-    it('should preen user history', function () {
-      let ref = beforeAfter({
-        daysAgo: 1,
-      });
-      let after = ref.after;
-
-      let history = [
-        {
-          date: '09/01/2012',
-          value: 0,
-        }, {
-          date: '10/01/2012',
-          value: 0,
-        }, {
-          date: '11/01/2012',
-          value: 2,
-        }, {
-          date: '12/01/2012',
-          value: 2,
-        }, {
-          date: '01/01/2013',
-          value: 1,
-        }, {
-          date: '01/15/2013',
-          value: 3,
-        }, {
-          date: '02/01/2013',
-          value: 2,
-        }, {
-          date: '02/15/2013',
-          value: 4,
-        }, {
-          date: '03/01/2013',
-          value: 3,
-        }, {
-          date: '03/15/2013',
-          value: 5,
-        }, {
-          date: '04/01/2013',
-          value: 4,
-        }, {
-          date: '04/15/2013',
-          value: 6,
-        }, {
-          date: '05/01/2013',
-          value: 5,
-        }, {
-          date: '05/15/2013',
-          value: 7,
-        }, {
-          date: '06/01/2013',
-          value: 6,
-        }, {
-          date: '06/15/2013',
-          value: 8,
-        }, {
-          date: '07/01/2013',
-          value: 7,
-        }, {
-          date: '07/15/2013',
-          value: 9,
-        }, {
-          date: '08/01/2013',
-          value: 8,
-        }, {
-          date: '08/15/2013',
-          value: 10,
-        }, {
-          date: '09/01/2013',
-          value: 9,
-        }, {
-          date: '09/15/2013',
-          value: 11,
-        }, {
-          date: '010/01/2013',
-          value: 10,
-        }, {
-          date: '010/15/2013',
-          value: 12,
-        }, {
-          date: '011/01/2013',
-          value: 12,
-        }, {
-          date: '011/02/2013',
-          value: 13,
-        }, {
-          date: '011/03/2013',
-          value: 14,
-        }, {
-          date: '011/04/2013',
-          value: 15,
-        },
-      ];
-
-      after.history = {
-        exp: _.cloneDeep(history),
-        todos: _.cloneDeep(history),
-      };
-      after.habits[0].history = _.cloneDeep(history);
-      after.fns.cron();
-      after.history.exp.pop();
-      after.history.todos.pop();
-      _.each([after.history.exp, after.history.todos, after.habits[0].history], function (arr) {
-        expect(_.map(arr, (x) => {
-          return x.value;
-        })).to.eql([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]);
-      });
-    });
-  });
-
   describe('Todos', () => {
     it('1 day missed', () => {
       let ref = beforeAfter({
diff --git a/test/common/preening.test.js b/test/common/preening.test.js
new file mode 100644
index 0000000000..f19a3c26b5
--- /dev/null
+++ b/test/common/preening.test.js
@@ -0,0 +1,70 @@
+import { preenHistory } from '../../common/script/preening';
+import moment from 'moment';
+import sinon from 'sinon'; // eslint-disable-line no-shadow
+
+function generateHistory (days) {
+  let history = [];
+  let now = Number(moment().toDate());
+
+  while (days > 0) {
+    history.push({
+      value: days,
+      date: Number(moment(now).subtract(days, 'days').toDate()),
+    });
+    days--;
+  }
+
+  return history;
+}
+
+describe('preenHistory', () => {
+  let clock;
+
+  beforeEach(() => {
+    // Replace system clocks so we can get predictable results
+    clock = sinon.useFakeTimers(Number(moment('2013-10-20').zone(0).startOf('day').toDate()), 'Date');
+  });
+  afterEach(() => {
+    return clock.restore();
+  });
+
+  it('does not modify history if all entries are more recent than cutoff (free users)', () => {
+    let h = generateHistory(60);
+    expect(preenHistory(_.cloneDeep(h), false, 0)).to.eql(h);
+  });
+
+  it('does not modify history if all entries are more recent than cutoff (subscribers)', () => {
+    let h = generateHistory(365);
+    expect(preenHistory(_.cloneDeep(h), true, 0)).to.eql(h);
+  });
+
+  it('does aggregate data in monthly entries before cutoff (free users)', () => {
+    let h = generateHistory(81); // Jumps to July
+    let preened = preenHistory(_.cloneDeep(h), false, 0);
+    expect(preened.length).to.eql(62); // Keeps 60 days + 2 entries per august and july
+  });
+
+  it('does aggregate data in monthly entries before cutoff (subscribers)', () => {
+    let h = generateHistory(396); // Jumps to September 2012
+    let preened = preenHistory(_.cloneDeep(h), true, 0);
+    expect(preened.length).to.eql(367); // Keeps 365 days + 2 entries per october and september
+  });
+
+  it('does aggregate data in monthly and yearly entries before cutoff (free users)', () => {
+    let h = generateHistory(731); // Jumps to October 21 2012
+    let preened = preenHistory(_.cloneDeep(h), false, 0);
+    expect(preened.length).to.eql(73); // Keeps 60 days + 11 montly entries and 2 yearly entry for 2011 and 2012
+  });
+
+  it('does aggregate data in monthly and yearly entries before cutoff (subscribers)', () => {
+    let h = generateHistory(1031); // Jumps to October 21 2012
+    let preened = preenHistory(_.cloneDeep(h), true, 0);
+    expect(preened.length).to.eql(380); // Keeps 365 days + 13 montly entries and 2 yearly entries for 2011 and 2010
+  });
+
+  it('correctly aggregates values', () => {
+    let h = generateHistory(63); // Compress last 3 days
+    let preened = preenHistory(_.cloneDeep(h), false, 0);
+    expect(preened[0].value).to.eql((61 + 62 + 63) / 3);
+  });
+});
diff --git a/test/helpers/api-v3-integration.helper.js b/test/helpers/api-v3-integration.helper.js
new file mode 100644
index 0000000000..530b275fb6
--- /dev/null
+++ b/test/helpers/api-v3-integration.helper.js
@@ -0,0 +1,279 @@
+/* eslint-disable no-use-before-define */
+
+import {
+  assign,
+  each,
+  isEmpty,
+  set,
+  times,
+} from 'lodash';
+import Q from 'q';
+import { MongoClient as mongo } from 'mongodb';
+import { v4 as generateUUID } from 'uuid';
+import superagent from 'superagent';
+import i18n from '../../common/script/src/i18n';
+i18n.translations = require('../../website/src/libs/api-v3/i18n').translations;
+
+const API_TEST_SERVER_PORT = 3003;
+
+class ApiUser {
+  constructor (options) {
+    assign(this, options);
+
+    this.get = _requestMaker(this, 'get');
+    this.post = _requestMaker(this, 'post');
+    this.put = _requestMaker(this, 'put');
+    this.del = _requestMaker(this, 'del');
+  }
+
+  update (options) {
+    return new Promise((resolve) => {
+      _updateDocument('users', this, options, resolve);
+    });
+  }
+}
+
+// Sets up an abject that can make all REST requests
+// If a user is passed in, the uuid and api token of
+// the user are used to make the requests
+export function requester (user = {}, additionalSets) {
+  return {
+    get: _requestMaker(user, 'get', additionalSets),
+    post: _requestMaker(user, 'post', additionalSets),
+    put: _requestMaker(user, 'put', additionalSets),
+    del: _requestMaker(user, 'del', additionalSets),
+  };
+}
+
+// Use this to verify error messages returned by the server
+// That way, if the translated string changes, the test
+// will not break. NOTE: it checks agains errors with string as well.
+export function translate (key, variables) {
+  const STRING_ERROR_MSG = 'Error processing the string. Please see Help > Report a Bug.';
+  const STRING_DOES_NOT_EXIST_MSG = /^String '.*' not found.$/;
+
+  let translatedString = i18n.t(key, variables);
+
+  expect(translatedString).to.not.be.empty;
+  expect(translatedString).to.not.eql(STRING_ERROR_MSG);
+  expect(translatedString).to.not.match(STRING_DOES_NOT_EXIST_MSG);
+
+  return translatedString;
+}
+
+// Useful for checking things that have been deleted,
+// but you no longer have access to,
+// like private parties or users
+export function checkExistence (collectionName, id) {
+  return new Promise((resolve, reject) => {
+    mongo.connect('mongodb://localhost/habitrpg_test', (connectionError, db) => {
+      if (connectionError) return reject(connectionError);
+      let collection = db.collection(collectionName);
+
+      collection.find({_id: id}, {_id: 1}).limit(1).toArray((findError, docs) => {
+        if (findError) return reject(findError);
+
+        let exists = docs.length > 0;
+
+        db.close();
+        resolve(exists);
+      });
+    });
+  });
+}
+
+// Creates a new user and returns it
+// If you need the user to have specific requirements,
+// such as a balance > 0, just pass in the adjustment
+// to the update object. If you want to adjust a nested
+// paramter, such as the number of wolf eggs the user has,
+// , you can do so by passing in the full path as a string:
+// { 'items.eggs.Wolf': 10 }
+export async function generateUser (update = {}) {
+  let username = generateUUID();
+  let password = 'password';
+  let email = `${username}@example.com`;
+
+  let request = _requestMaker({}, 'post');
+
+  let user = await request('/user/auth/local/register', {
+    username,
+    email,
+    password,
+    confirmPassword: password,
+  });
+
+  return Q.promise((resolve) => {
+    _updateDocument('users', user, update, () => {
+      let apiUser = new ApiUser(user);
+
+      resolve(apiUser);
+    });
+  });
+}
+
+// Generates a new group. Requires a user object, which
+// will will become the groups leader. Takes an update
+// argument which will update group
+export function generateGroup (leader, details = {}, update = {}) {
+  return new Promise((resolve, reject) => {
+    leader.post('/groups', details).then((group) => {
+      _updateDocument('groups', group, update, () => {
+        resolve(group);
+      });
+    }).catch(reject);
+  });
+}
+
+// This is generate group + the ability to create
+// real users to populate it. The settings object
+// takes in:
+// members: Number - the number of group members to create. Defaults to 0.
+// inivtes: Number - the number of users to create and invite to the group. Defaults to 0.
+// groupDetails: Object - how to initialize the group
+// leaderDetails: Object - defaults for the leader, defaults with a gem balance so the user
+// can create the group
+//
+// Returns an object with
+// members: an array of user objects that correspond to the members of the group
+// invitees: an array of user objects that correspond to the invitees of the group
+// leader: the leader user object
+// group: the group object
+export async function createAndPopulateGroup (settings = {}) {
+  let numberOfMembers = settings.members || 0;
+  let numberOfInvites = settings.invites || 0;
+  let groupDetails = settings.groupDetails;
+  let leaderDetails = settings.leaderDetails || { balance: 10 };
+
+  let groupLeader = await generateUser(leaderDetails);
+  let group = await generateGroup(groupLeader, groupDetails);
+
+  let members = await Q.all(
+    times(numberOfMembers, () => {
+      return generateUser();
+    })
+  );
+
+  let groupTypes = {
+    guild: { guilds: [group._id] },
+    party: { 'party._id': group._id },
+  };
+
+  let memberPromises = members.map((member) => {
+    return member.update(groupTypes[group.type]);
+  });
+
+  await Q.all(memberPromises);
+
+  let invitees = await Q.all(
+    times(numberOfInvites, () => {
+      return generateUser();
+    })
+  );
+
+  let invitationPromises = invitees.map((invitee) => {
+    return groupLeader.post(`/groups/${group._id}/invite`, {
+      uuids: [invitee._id],
+    });
+  });
+
+  await Q.all(invitationPromises);
+
+  return {
+    groupLeader,
+    group,
+    members,
+    invitees,
+  };
+}
+
+// Specifically helpful for the GET /groups tests,
+// resets the db to an empty state and creates a tavern document
+export function resetHabiticaDB () {
+  return new Promise((resolve, reject) => {
+    mongo.connect('mongodb://localhost/habitrpg_test', (err, db) => {
+      if (err) return reject(err);
+
+      db.dropDatabase((dbErr) => {
+        if (dbErr) return reject(dbErr);
+        let groups = db.collection('groups');
+
+        groups.insertOne({
+          _id: 'habitrpg',
+          chat: [],
+          leader: '9',
+          name: 'HabitRPG',
+          type: 'guild',
+          privacy: 'public',
+          members: [],
+        }, (insertErr) => {
+          if (insertErr) return reject(insertErr);
+
+          db.close();
+          resolve();
+        });
+      });
+    });
+  });
+}
+
+function _requestMaker (user, method, additionalSets) {
+  return (route, send, query) => {
+    return new Promise((resolve, reject) => {
+      let request = superagent[method](`http://localhost:${API_TEST_SERVER_PORT}/api/v3${route}`)
+        .accept('application/json');
+
+      if (user && user._id && user.apiToken) {
+        request
+          .set('x-api-user', user._id)
+          .set('x-api-key', user.apiToken);
+      }
+
+      if (additionalSets) {
+        request.set(additionalSets);
+      }
+
+      request
+        .query(query)
+        .send(send)
+        .end((err, response) => {
+          if (err) {
+            if (!err.response) return reject(err);
+
+            return reject({
+              code: err.status,
+              error: err.response.body.error,
+              message: err.response.body.message,
+            });
+          }
+
+          resolve(response.body);
+        });
+    });
+  };
+}
+
+function _updateDocument (collectionName, doc, update, cb) {
+  if (isEmpty(update)) {
+    return cb();
+  }
+
+  mongo.connect('mongodb://localhost/habitrpg_test', (connectErr, db) => {
+    if (connectErr) throw new Error(`Error connecting to database when updating ${collectionName} collection: ${connectErr}`);
+
+    let collection = db.collection(collectionName);
+
+    collection.updateOne({ _id: doc._id }, { $set: update }, (updateErr) => {
+      if (updateErr) throw new Error(`Error updating ${collectionName}: ${updateErr}`);
+      _updateLocalDocument(doc, update);
+      db.close();
+      cb();
+    });
+  });
+}
+
+function _updateLocalDocument (doc, update) {
+  each(update, (value, param) => {
+    set(doc, param, value);
+  });
+}
diff --git a/website/src/controllers/api-v3/groups.js b/website/src/controllers/api-v3/groups.js
index 85ba270935..8203e00b1b 100644
--- a/website/src/controllers/api-v3/groups.js
+++ b/website/src/controllers/api-v3/groups.js
@@ -117,12 +117,13 @@ api.getGroups = {
     // If no valid value for type was supplied, return an error
     if (queries.length === 0) throw new BadRequest(res.t('groupTypesRequired'));
 
-    let results = await Q.all(queries); // TODO we would like not to return a single big array but Q doesn't support the funtionality https://github.com/kriskowal/q/issues/328
+    // TODO we would like not to return a single big array but Q doesn't support the funtionality https://github.com/kriskowal/q/issues/328
+    let results = _.reduce(await Q.all(queries), (previousValue, currentValue) => {
+      if (_.isEmpty(currentValue)) return previousValue; // don't add anything to the results if the query returned null or an empty array
+      return previousValue.concat(Array.isArray(currentValue) ? currentValue : [currentValue]); // otherwise concat the new results to the previousValue
+    }, []);
 
-    res.respond(200, _.reduce(results, (m, v) => {
-      if (_.isEmpty(v)) return m;
-      return m.concat(Array.isArray(v) ? v : [v]);
-    }, []));
+    res.respond(200, results);
   },
 };
 
diff --git a/website/src/controllers/api-v3/tasks.js b/website/src/controllers/api-v3/tasks.js
index 84ccf0a221..cee1ba4527 100644
--- a/website/src/controllers/api-v3/tasks.js
+++ b/website/src/controllers/api-v3/tasks.js
@@ -2,6 +2,7 @@ import { authWithHeaders } from '../../middlewares/api-v3/auth';
 import cron from '../../middlewares/api-v3/cron';
 import { sendTaskWebhook } from '../../libs/api-v3/webhook';
 import * as Tasks from '../../models/task';
+import { model as Challenge } from '../../models/challenge';
 import {
   NotFound,
   NotAuthorized,
@@ -10,70 +11,213 @@ import {
 import shared from '../../../../common';
 import Q from 'q';
 import _ from 'lodash';
+import moment from 'moment';
 import scoreTask from '../../../../common/script/api-v3/scoreTask';
-import { preenHistory } from '../../../../common/script/api-v3/preenHistory';
+import { preenHistory } from '../../../../common/script/api-v3/preening';
 
 let api = {};
 
+// challenge must be passed only when a challenge task is being created
+async function _createTasks (req, res, user, challenge) {
+  let toSave = Array.isArray(req.body) ? req.body : [req.body];
+
+  toSave = toSave.map(taskData => {
+    // Validate that task.type is valid
+    if (!taskData || Tasks.tasksTypes.indexOf(taskData.type) === -1) throw new BadRequest(res.t('invalidTaskType'));
+
+    let taskType = taskData.type;
+    let newTask = new Tasks[taskType](Tasks.Task.sanitizeCreate(taskData));
+
+    if (challenge) {
+      newTask.challenge.id = challenge.id;
+    } else {
+      newTask.userId = user._id;
+    }
+
+    // Validate that the task is valid and throw if it isn't
+    // otherwise since we're saving user/challenge and task in parallel it could save the user/challenge with a tasksOrder that doens't match reality
+    let validationErrors = newTask.validateSync();
+    if (validationErrors) throw validationErrors;
+
+    // Otherwise update the user/challenge
+    (challenge || user).tasksOrder[`${taskType}s`].unshift(newTask._id);
+
+    return newTask;
+  }).map(task => task.save({ // If all tasks are valid (this is why it's not in the previous .map()), save everything, withough running validation again
+    validateBeforeSave: false,
+  }));
+
+  toSave.unshift((challenge || user).save());
+
+  let tasks = await Q.all(toSave);
+  tasks.splice(0, 1); // Remove user or challenge
+  return tasks;
+}
+
 /**
- * @api {post} /tasks Create a new task. Can be passed an object to create a single task or an array of objects to create multiple tasks.
+ * @api {post} /tasks/user Create a new task belonging to the autheticated user. Can be passed an object to create a single task or an array of objects to create multiple tasks.
  * @apiVersion 3.0.0
- * @apiName CreateTask
+ * @apiName CreateUserTasks
  * @apiGroup Task
  *
  * @apiSuccess {Object|Array} task The newly created task(s)
  */
-api.createTask = {
+api.createUserTasks = {
   method: 'POST',
-  url: '/tasks',
+  url: '/tasks/user',
   middlewares: [authWithHeaders(), cron],
   async handler (req, res) {
-    let tasksData = Array.isArray(req.body) ? req.body : [req.body];
-    let user = res.locals.user;
-
-    let toSave = tasksData.map(taskData => {
-      // Validate that task.type is valid
-      if (!taskData || Tasks.tasksTypes.indexOf(taskData.type) === -1) throw new BadRequest(res.t('invalidTaskType'));
-
-      let taskType = taskData.type;
-      let newTask = new Tasks[taskType](Tasks.Task.sanitizeCreate(taskData));
-      newTask.userId = user._id;
-
-      // Validate that the task is valid and throw if it isn't
-      // otherwise since we're saving user and task in parallel it could save the user with a tasksOrder that doens't match reality
-      let validationErrors = newTask.validateSync();
-      if (validationErrors) throw validationErrors;
-
-      // Otherwise update the user
-      user.tasksOrder[`${taskType}s`].unshift(newTask._id);
-
-      return newTask;
-    });
-
-    // If all tasks are valid, save everything, withough running validation again
-    toSave = toSave.map(task => task.save({
-      validateBeforeSave: false,
-    }));
-    toSave.unshift(user.save());
-    let results = await Q.all(toSave);
-
-    if (results.length === 2) { // Just one task created
-      res.respond(201, results[1]);
-    } else {
-      results.splice(0, 1); // remove the user
-      res.respond(201, results);
-    }
+    let tasks = await _createTasks(req, res, res.locals.user);
+    res.respond(201, tasks.length === 1 ? tasks[0] : tasks);
   },
 };
 
 /**
- * @api {get} /tasks Get an user's tasks
+ * @api {post} /tasks/challenge/:challengeId Create a new task belonging to the challenge. Can be passed an object to create a single task or an array of objects to create multiple tasks.
+ * @apiVersion 3.0.0
+ * @apiName CreateChallengeTasks
+ * @apiGroup Task
+ *
+ * @apiParam {UUID} challengeId The id of the challenge the new task(s) will belong to.
+ *
+ * @apiSuccess {Object|Array} task The newly created task(s)
+ */
+api.createChallengeTasks = {
+  method: 'POST',
+  url: '/tasks/challenge/:challengeId',
+  middlewares: [authWithHeaders(), cron],
+  async handler (req, res) {
+    req.checkQuery('challengeId', res.t('challengeIdRequired')).notEmpty().isUUID();
+
+    let reqValidationErrors = req.validationErrors();
+    if (reqValidationErrors) throw reqValidationErrors;
+
+    let user = res.local.user;
+    let challengeId = req.params.challengeId;
+
+    let challenge = await Challenge.findOne({_id: challengeId}).exec();
+
+    // If the challenge does not exist, or if it exists but user is not the leader -> throw error
+    if (!challenge || user.challenges.indexOf(challengeId) === -1) throw new NotFound(res.t('challengeNotFound'));
+    if (challenge.leader !== user._id) throw new NotAuthorized(res.t('onlyChalLeaderEditTasks'));
+
+    let tasks = await _createTasks(req, res, user, challenge);
+    res.respond(201, tasks.length === 1 ? tasks[0] : tasks);
+
+    // If adding tasks to a challenge -> sync users
+    if (challenge) challenge.addTasks(tasks); // TODO catch/log
+  },
+};
+
+// challenge must be passed only when a challenge task is being created
+async function _getTasks (req, res, user, challenge) {
+  let query = challenge ? {'challenge.id': challenge.id, userId: {$exists: false}} : {userId: user._id};
+  let type = req.query.type;
+
+  if (type) {
+    query.type = type;
+    if (type === 'todo') query.completed = false; // Exclude completed todos
+  } else {
+    query.$or = [ // Exclude completed todos
+      {type: 'todo', completed: false},
+      {type: {$in: ['habit', 'daily', 'reward']}},
+    ];
+  }
+
+  if (req.query.includeCompletedTodos === 'true' && (!type || type === 'todo')) {
+    if (challenge) throw new BadRequest(res.t('noCompletedTodosChallenge')); // no completed todos for challenges
+
+    let queryCompleted = Tasks.Task.find({
+      type: 'todo',
+      completed: true,
+    }).limit(30).sort({ // TODO add ability to pick more than 30 completed todos
+      dateCompleted: 1,
+    });
+
+    let results = await Q.all([
+      queryCompleted.exec(),
+      Tasks.Task.find(query).exec(),
+    ]);
+
+    res.respond(200, results[1].concat(results[0]));
+  } else {
+    let tasks = await Tasks.Task.find(query).exec();
+    res.respond(200, tasks);
+  }
+}
+
+/**
+ * @api {get} /tasks/user Get an user's tasks
+ * @apiVersion 3.0.0
+ * @apiName GetUserTasks
+ * @apiGroup Task
+ *
+ * @apiParam {string="habit","daily","todo","reward"} type Optional query parameter to return just a type of tasks
+ * @apiParam {boolean} includeCompletedTodos Optional query parameter to include completed todos when "type" is "todo". Only valid whe "tasksOwner" is "user".
+ *
+ * @apiSuccess {Array} tasks An array of task objects
+ */
+api.getUserTasks = {
+  method: 'GET',
+  url: '/tasks/user',
+  middlewares: [authWithHeaders(), cron],
+  async handler (req, res) {
+    req.checkQuery('type', res.t('invalidTaskType')).optional().isIn(Tasks.tasksTypes);
+
+    let validationErrors = req.validationErrors();
+    if (validationErrors) throw validationErrors;
+
+    await _getTasks(req, res, res.locals.user);
+  },
+};
+
+/**
+ * @api {get} /tasks/challenge/:challengeId Get a challenge's tasks
+ * @apiVersion 3.0.0
+ * @apiName GetChallengeTasks
+ * @apiGroup Task
+ *
+ * @apiParam {UUID} challengeId The id of the challenge from which to retrieve the tasks.
+ *
+ * @apiParam {string="habit","daily","todo","reward"} type Optional query parameter to return just a type of tasks
+ *
+ * @apiSuccess {Array} tasks An array of task objects
+ */
+api.getChallengeTasks = {
+  method: 'GET',
+  url: '/tasks/challenge/:challengeId',
+  middlewares: [authWithHeaders(), cron],
+  async handler (req, res) {
+    req.checkQuery('challengeId', res.t('challengeIdRequired')).notEmpty().isUUID();
+    req.checkQuery('type', res.t('invalidTaskType')).optional().isIn(Tasks.tasksTypes);
+
+    let validationErrors = req.validationErrors();
+    if (validationErrors) throw validationErrors;
+
+    let user = res.local.user;
+    let challengeId = req.params.challengeId;
+
+    let challenge = await Challenge.findOne({_id: challengeId}).select('leader').exec();
+
+    // If the challenge does not exist, or if it exists but user is not a member, not the leader and not an admin -> throw error
+    if (!challenge || (user.challenges.indexOf(challengeId) === -1 && challenge.leader !== user._id && !user.contributor.admin)) { // eslint-disable-line no-extra-parens
+      throw new NotFound(res.t('challengeNotFound'));
+    }
+
+    await _getTasks(req, res, res.locals.user, challenge);
+  },
+};
+
+/**
+ * @api {get} /tasks/:tasksOwner/:challengeId Get an user's tasks
  * @apiVersion 3.0.0
  * @apiName GetTasks
  * @apiGroup Task
  *
+ * @apiParam {string="user","challenge"} tasksOwner Query parameter to return tasks belonging to a challenge (specifying the "challengeId" parameter) or to the autheticated user.
+ * @apiParam {UUID} challengeId Optional query parameter. If "tasksOwner" is "challenge" then required to specify the challenge id.
  * @apiParam {string="habit","daily","todo","reward"} type Optional query parameter to return just a type of tasks
- * @apiParam {boolean} includeCompletedTodos Optional query parameter to include completed todos when "type" is "todo"
+ * @apiParam {boolean} includeCompletedTodos Optional query parameter to include completed todos when "type" is "todo". Only valid whe "tasksOwner" is "user".
  *
  * @apiSuccess {Array} tasks An array of task objects
  */
@@ -82,13 +226,11 @@ api.getTasks = {
   url: '/tasks',
   middlewares: [authWithHeaders(), cron],
   async handler (req, res) {
-    req.checkQuery('type', res.t('invalidTaskType')).optional().isIn(Tasks.tasksTypes);
-
-    let validationErrors = req.validationErrors();
-    if (validationErrors) throw validationErrors;
-
     let user = res.locals.user;
-    let query = {userId: user._id};
+    let challengeId = req.query.challengeId;
+    let challenge;
+
+    let query = challenge ? {'challenge.id': challengeId, userId: {$exists: false}} : {userId: user._id};
     let type = req.query.type;
 
     if (type) {
@@ -102,6 +244,8 @@ api.getTasks = {
     }
 
     if (req.query.includeCompletedTodos === 'true' && (!type || type === 'todo')) {
+      if (challengeId) throw new BadRequest(res.t('noCompletedTodosChallenge'));
+
       let queryCompleted = Tasks.Task.find({
         type: 'todo',
         completed: true,
@@ -146,10 +290,19 @@ api.getTask = {
 
     let task = await Tasks.Task.findOne({
       _id: req.params.taskId,
-      userId: user._id,
     }).exec();
 
-    if (!task) throw new NotFound(res.t('taskNotFound'));
+    if (!task) {
+      throw new NotFound(res.t('taskNotFound'));
+    } else if (!task.userId) { // If the task belongs to a challenge make sure the user has rights
+      let challenge = await Challenge.find().selec({_id: task.challenge.id}).select('leader').exec();
+      if (!challenge || (user.challenges.indexOf(task.challenge.id) === -1 && challenge.leader !== user._id && !user.contributor.admin)) { // eslint-disable-line no-extra-parens
+        throw new NotFound(res.t('taskNotFound'));
+      }
+    } else if (task.userId !== user._id) { // If the task is owned by an user make it's the current one
+      throw new NotFound(res.t('taskNotFound'));
+    }
+
     res.respond(200, task);
   },
 };
@@ -170,6 +323,7 @@ api.updateTask = {
   middlewares: [authWithHeaders(), cron],
   async handler (req, res) {
     let user = res.locals.user;
+    let challenge;
 
     req.checkParams('taskId', res.t('taskIdRequired')).notEmpty().isUUID();
     // TODO check that req.body isn't empty
@@ -180,10 +334,17 @@ api.updateTask = {
 
     let task = await Tasks.Task.findOne({
       _id: req.params.taskId,
-      userId: user._id,
     }).exec();
 
-    if (!task) throw new NotFound(res.t('taskNotFound'));
+    if (!task) {
+      throw new NotFound(res.t('taskNotFound'));
+    } else if (!task.userId) { // If the task belongs to a challenge make sure the user has rights
+      challenge = await Challenge.find().selec({_id: task.challenge.id}).select('leader').exec();
+      if (!challenge) throw new NotFound(res.t('challengeNotFound'));
+      if (challenge.leader !== user._id) throw new NotAuthorized(res.t('onlyChalLeaderEditTasks'));
+    } else if (task.userId !== user._id) { // If the task is owned by an user make it's the current one
+      throw new NotFound(res.t('taskNotFound'));
+    }
 
     // If checklist is updated -> replace the original one
     if (req.body.checklist) {
@@ -206,6 +367,7 @@ api.updateTask = {
 
     let savedTask = await task.save();
     res.respond(200, savedTask);
+    if (challenge) challenge.updateTask(savedTask); // TODO catch/log
   },
 };
 
@@ -313,11 +475,27 @@ api.scoreTask = {
         }).exec();
 
         chalTask.value += delta;
+
         if (chalTask.type === 'habit' || chalTask.type === 'daily') {
-          chalTask.history.push({value: chalTask.value, date: Number(new Date())});
-          // TODO 1. treat challenges as subscribed users for preening 2. it's expensive to do it at every score - how to have it happen once like for cron?
-          chalTask.history = preenHistory(user, chalTask.history);
-          chalTask.markModified('history');
+          // Add only one history entry per day
+          if (moment(chalTask.history[chalTask.history.length - 1].date).isSame(new Date(), 'day')) {
+            chalTask.history[chalTask.history.length - 1] = {
+              date: Number(new Date()),
+              value: chalTask.value,
+            };
+            chalTask.markModified(`history.${chalTask.history.length - 1}`);
+          } else {
+            chalTask.history.push({
+              date: Number(new Date()),
+              value: chalTask.value,
+            });
+
+            // Only preen task history once a day when the task is scored first
+            if (chalTask.history.length > 365) {
+              chalTask.history = preenHistory(chalTask.history, true); // true means the challenge will retain as much entries as a subscribed user
+              chalTask.markModified(`history.${chalTask.history.length - 1}`);
+            }
+          }
         }
 
         await chalTask.save();
@@ -330,6 +508,7 @@ api.scoreTask = {
 
 // completed todos cannot be moved, they'll be returned ordered by date of completion
 // TODO check that it works when a tag is selected or todos are split between dated and due
+// TODO support challenges?
 /**
  * @api {post} /tasks/move/:taskId/to/:position Move a task to a new position
  * @apiVersion 3.0.0
@@ -361,7 +540,7 @@ api.moveTask = {
     }).exec();
 
     if (!task) throw new NotFound(res.t('taskNotFound'));
-    if (task.type === 'todo' && task.completed) throw new NotFound(res.t('cantMoveCompletedTodo'));
+    if (task.type === 'todo' && task.completed) throw new BadRequest(res.t('cantMoveCompletedTodo'));
     let order = user.tasksOrder[`${task.type}s`];
     let currentIndex = order.indexOf(task._id);
 
@@ -397,6 +576,7 @@ api.addChecklistItem = {
   middlewares: [authWithHeaders(), cron],
   async handler (req, res) {
     let user = res.locals.user;
+    let challenge;
 
     req.checkParams('taskId', res.t('taskIdRequired')).notEmpty().isUUID();
     // TODO check that req.body isn't empty and is an array
@@ -406,16 +586,25 @@ api.addChecklistItem = {
 
     let task = await Tasks.Task.findOne({
       _id: req.params.taskId,
-      userId: user._id,
     }).exec();
 
-    if (!task) throw new NotFound(res.t('taskNotFound'));
+    if (!task) {
+      throw new NotFound(res.t('taskNotFound'));
+    } else if (!task.userId) { // If the task belongs to a challenge make sure the user has rights
+      challenge = await Challenge.find().selec({_id: task.challenge.id}).select('leader').exec();
+      if (!challenge) throw new NotFound(res.t('challengeNotFound'));
+      if (challenge.leader !== user._id) throw new NotAuthorized(res.t('onlyChalLeaderEditTasks'));
+    } else if (task.userId !== user._id) { // If the task is owned by an user make it's the current one
+      throw new NotFound(res.t('taskNotFound'));
+    }
+
     if (task.type !== 'daily' && task.type !== 'todo') throw new BadRequest(res.t('checklistOnlyDailyTodo'));
 
     task.checklist.push(Tasks.Task.sanitizeChecklist(req.body));
     let savedTask = await task.save();
 
     res.respond(200, savedTask); // TODO what to return
+    if (challenge) challenge.updateTask(savedTask);
   },
 };
 
@@ -478,6 +667,7 @@ api.updateChecklistItem = {
   middlewares: [authWithHeaders(), cron],
   async handler (req, res) {
     let user = res.locals.user;
+    let challenge;
 
     req.checkParams('taskId', res.t('taskIdRequired')).notEmpty().isUUID();
     req.checkParams('itemId', res.t('itemIdRequired')).notEmpty().isUUID();
@@ -487,10 +677,17 @@ api.updateChecklistItem = {
 
     let task = await Tasks.Task.findOne({
       _id: req.params.taskId,
-      userId: user._id,
     }).exec();
 
-    if (!task) throw new NotFound(res.t('taskNotFound'));
+    if (!task) {
+      throw new NotFound(res.t('taskNotFound'));
+    } else if (!task.userId) { // If the task belongs to a challenge make sure the user has rights
+      challenge = await Challenge.find().selec({_id: task.challenge.id}).select('leader').exec();
+      if (!challenge) throw new NotFound(res.t('challengeNotFound'));
+      if (challenge.leader !== user._id) throw new NotAuthorized(res.t('onlyChalLeaderEditTasks'));
+    } else if (task.userId !== user._id) { // If the task is owned by an user make it's the current one
+      throw new NotFound(res.t('taskNotFound'));
+    }
     if (task.type !== 'daily' && task.type !== 'todo') throw new BadRequest(res.t('checklistOnlyDailyTodo'));
 
     let item = _.find(task.checklist, {_id: req.params.itemId});
@@ -500,6 +697,7 @@ api.updateChecklistItem = {
     let savedTask = await task.save();
 
     res.respond(200, savedTask); // TODO what to return
+    if (challenge) challenge.updateTask(savedTask);
   },
 };
 
@@ -520,6 +718,7 @@ api.removeChecklistItem = {
   middlewares: [authWithHeaders(), cron],
   async handler (req, res) {
     let user = res.locals.user;
+    let challenge;
 
     req.checkParams('taskId', res.t('taskIdRequired')).notEmpty().isUUID();
     req.checkParams('itemId', res.t('itemIdRequired')).notEmpty().isUUID();
@@ -529,10 +728,17 @@ api.removeChecklistItem = {
 
     let task = await Tasks.Task.findOne({
       _id: req.params.taskId,
-      userId: user._id,
     }).exec();
 
-    if (!task) throw new NotFound(res.t('taskNotFound'));
+    if (!task) {
+      throw new NotFound(res.t('taskNotFound'));
+    } else if (!task.userId) { // If the task belongs to a challenge make sure the user has rights
+      challenge = await Challenge.find().selec({_id: task.challenge.id}).select('leader').exec();
+      if (!challenge) throw new NotFound(res.t('challengeNotFound'));
+      if (challenge.leader !== user._id) throw new NotAuthorized(res.t('onlyChalLeaderEditTasks'));
+    } else if (task.userId !== user._id) { // If the task is owned by an user make it's the current one
+      throw new NotFound(res.t('taskNotFound'));
+    }
     if (task.type !== 'daily' && task.type !== 'todo') throw new BadRequest(res.t('checklistOnlyDailyTodo'));
 
     let itemI = _.findIndex(task.checklist, {_id: req.params.itemId});
@@ -540,8 +746,9 @@ api.removeChecklistItem = {
 
     task.checklist.splice(itemI, 1);
 
-    await task.save();
+    let savedTask = await task.save();
     res.respond(200, {}); // TODO what to return
+    if (challenge) challenge.updateTask(savedTask);
   },
 };
 
@@ -629,22 +836,64 @@ api.removeTagFromTask = {
   },
 };
 
-// Remove a task from user.tasksOrder
-function _removeTaskTasksOrder (user, taskId) {
-  // Loop through all lists and when the task is found, remove it and return
-  for (let i = 0; i < Tasks.tasksTypes.length; i++) {
-    let list = user.tasksOrder[`${Tasks.tasksTypes[i]}s`];
-    let index = list.indexOf(taskId);
+// Remove a task from (user|challenge).tasksOrder
+function _removeTaskTasksOrder (userOrChallenge, taskId, taskType) {
+  let list = userOrChallenge.tasksOrder[`${taskType}s`];
+  let index = list.indexOf(taskId);
 
-    if (index !== -1) {
-      list.splice(index, 1);
-      break;
-    }
-  }
-
-  return;
+  if (index !== -1) list.splice(index, 1);
 }
 
+// TODO this method needs some limitation, like to check if the challenge is really broken?
+/**
+ * @api {post} /tasks/unlink/:taskId Unlink a challenge task
+ * @apiVersion 3.0.0
+ * @apiName UnlinkTask
+ * @apiGroup Task
+ *
+ * @apiParam {UUID} taskId The task _id
+ *
+ * @apiSuccess {object} empty An empty object
+ */
+api.unlinkTask = {
+  method: 'POST',
+  url: '/tasks/unlink/:taskId',
+  middlewares: [authWithHeaders(), cron],
+  async handler (req, res) {
+    req.checkParams('taskId', res.t('taskIdRequired')).notEmpty().isUUID();
+    req.checkQuery('keep', res.t('keepOrRemove')).notEmpty().isIn(['keep', 'remove']);
+
+    let validationErrors = req.validationErrors();
+    if (validationErrors) throw validationErrors;
+
+    let user = res.locals.user;
+    let keep = req.query.keep;
+    let taskId = req.params.taskId;
+
+    let task = await Tasks.Task.findOne({
+      _id: taskId,
+      userId: user._id,
+    }).exec();
+
+    if (!task) throw new NotFound(res.t('taskNotFound'));
+    if (!task.challenge.id) throw new BadRequest(res.t('cantOnlyUnlinkChalTask'));
+
+    if (keep === 'keep') {
+      task.challenge = {};
+      await task.save();
+    } else { // remove
+      if (task.type !== 'todo' || !task.completed) { // eslint-disable-line no-lonely-if
+        _removeTaskTasksOrder(user, taskId, task.type);
+        await Q.all([user.save(), task.remove()]);
+      } else {
+        await task.remove();
+      }
+    }
+
+    res.respond(200, {}); // TODO what to return
+  },
+};
+
 /**
  * @api {delete} /task/:taskId Delete a user task given its id
  * @apiVersion 3.0.0
@@ -661,24 +910,37 @@ api.deleteTask = {
   middlewares: [authWithHeaders(), cron],
   async handler (req, res) {
     let user = res.locals.user;
+    let challenge;
 
     req.checkParams('taskId', res.t('taskIdRequired')).notEmpty().isUUID();
 
     let validationErrors = req.validationErrors();
     if (validationErrors) throw validationErrors;
 
-    let task = await Tasks.Task.findOne({
-      _id: req.params.taskId,
-      userId: user._id,
-    }).exec();
+    let taskId = req.params.taskId;
+    let task = await Tasks.Task.findById(taskId).exec();
 
-    if (!task) throw new NotFound(res.t('taskNotFound'));
-    if (task.challenge.id) throw new NotAuthorized(res.t('cantDeleteChallengeTasks'));
+    if (!task) {
+      throw new NotFound(res.t('taskNotFound'));
+    } else if (!task.userId) { // If the task belongs to a challenge make sure the user has rights
+      challenge = await Challenge.find().selec({_id: task.challenge.id}).select('leader').exec();
+      if (!challenge) throw new NotFound(res.t('challengeNotFound'));
+      if (challenge.leader !== user._id) throw new NotAuthorized(res.t('onlyChalLeaderEditTasks'));
+    } else if (task.userId !== user._id) { // If the task is owned by an user make it's the current one
+      throw new NotFound(res.t('taskNotFound'));
+    } else if (task.userId && task.challenge.id) {
+      throw new NotAuthorized(res.t('cantDeleteChallengeTasks'));
+    }
 
-    _removeTaskTasksOrder(user, req.params.taskId);
-    await Q.all([user.save(), task.remove()]);
+    if (task.type !== 'todo' || !task.completed) {
+      _removeTaskTasksOrder(challenge || user, taskId, task.type);
+      await Q.all([(challenge || user).save(), task.remove()]);
+    } else {
+      await task.remove();
+    }
 
     res.respond(200, {});
+    if (challenge) challenge.removeTask(task);
   },
 };
 
diff --git a/website/src/middlewares/api-v3/cron.js b/website/src/middlewares/api-v3/cron.js
index 0d6d46b900..aaebc476dc 100644
--- a/website/src/middlewares/api-v3/cron.js
+++ b/website/src/middlewares/api-v3/cron.js
@@ -6,9 +6,10 @@ import {
 import cron from '../../../../common/script/api-v3/cron';
 import common from '../../../../common';
 import Task from '../../models/task';
+import Q from 'q';
 // import Group from '../../models/group';
 
-// TODO check that it's usef everywhere
+// TODO check that it's used everywhere
 export default function cronMiddleware (req, res, next) {
   let user = res.locals.user;
   let analytics = res.analytics;
@@ -26,7 +27,7 @@ export default function cronMiddleware (req, res, next) {
       {type: {$in: ['habit', 'daily', 'reward']}},
     ],
   }).exec()
-  .then((tasks) => {
+  .then(tasks => {
     let tasksByType = {habits: [], dailys: [], todos: [], rewards: []};
     tasks.forEach(task => tasksByType[`${task.type}s`].push(task));
 
@@ -34,6 +35,7 @@ export default function cronMiddleware (req, res, next) {
     cron({user, tasksByType, now, daysMissed, analytics});
 
     // Clean completed todos - 30 days for free users, 90 for subscribers
+    // Do not delete challenges completed todos TODO unless the task is broken?
     Task.remove({
       userId: user._id,
       type: 'todo',
@@ -41,6 +43,7 @@ export default function cronMiddleware (req, res, next) {
       dateCompleted: {
         $lt: moment(now).subtract(user.isSubscribed() ? 90 : 30, 'days'),
       },
+      'challenge.id': {$exists: false},
     }).exec(); // TODO catch error or at least log it
 
     let ranCron = user.isModified();
@@ -49,7 +52,15 @@ export default function cronMiddleware (req, res, next) {
     // if (ranCron) res.locals.wasModified = true; // TODO remove?
     if (!ranCron) return next();
     // TODO Group.tavernBoss(user, progress);
-    if (!quest || true /* TODO remove */) return user.save(next);
+    if (!quest || true /* TODO remove */) {
+      // Save user and tasks
+      let toSave = [user.save()];
+      tasks.forEach(task => {
+        if (task.isModified) toSave.push(task.save());
+      });
+
+      return Q.all(toSave).then(() => next()).catch(next);
+    }
 
     // If user is on a quest, roll for boss & player, or handle collections
     // FIXME this saves user, runs db updates, loads user. Is there a better way to handle this?
diff --git a/website/src/models/challenge.js b/website/src/models/challenge.js
index 00ab26a491..b675a7833e 100644
--- a/website/src/models/challenge.js
+++ b/website/src/models/challenge.js
@@ -4,6 +4,7 @@ import validator from 'validator';
 import baseModel from '../libs/api-v3/baseModel';
 import _ from 'lodash';
 import * as Tasks from './task';
+import { model as User } from './user';
 
 let Schema = mongoose.Schema;
 
@@ -30,37 +31,18 @@ schema.plugin(baseModel, {
   noSet: ['_id', 'memberCount', 'challengeCount', 'tasksOrder'],
 });
 
-
-// Syncing logic
-
+// Takes a Task document and return a plain object of attributes that can be synced to the user
 function _syncableAttrs (task) {
-  let t = task.toObject(); // lodash doesn't seem to like _.omit on EmbeddedDocument
+  let t = task.toObject(); // lodash doesn't seem to like _.omit on Document
   // only sync/compare important attrs
-  let omitAttrs = ['userId', 'challenge', 'history', 'tags', 'completed', 'streak', 'notes']; // TODO use whitelist instead of blacklist?
+  let omitAttrs = ['userId', 'challenge', 'history', 'tags', 'completed', 'streak', 'notes']; // TODO what to do with updatedAt?
   if (t.type !== 'reward') omitAttrs.push('value');
   return _.omit(t, omitAttrs);
 }
 
-// TODO redo
-// Compare whether any changes have been made to tasks. If so, we'll want to sync those changes to subscribers
-/* function comparableData(obj) {
-  return JSON.stringify(
-    _(obj.habits.concat(obj.dailys).concat(obj.todos).concat(obj.rewards))
-      .sortBy('id') // we don't want to update if they're sort-order is different
-      .transform(function(result, task){
-        result.push(syncableAttrs(task));
-      })
-      .value())
-}
-
-ChallengeSchema.methods.isOutdated = function isChallengeOutdated (newData) {
-  return comparableData(this) !== comparableData(newData);
-}*/
-
-// Syncs all new tasks, deleted tasks, etc to the user object
-schema.methods.syncToUser = function syncChallengeToUser (user) {
-  if (!user) throw new Error('User required.');
-
+// Sync challenge to user, including tasks and tags.
+// Used when user joins the challenge or to force sync.
+schema.methods.syncToUser = async function syncChallengeToUser (user) {
   let challenge = this;
   challenge.shortName = challenge.shortName || challenge.name;
 
@@ -84,8 +66,7 @@ schema.methods.syncToUser = function syncChallengeToUser (user) {
     });
   }
 
-  // Sync new tasks and updated tasks
-  return Q.all([
+  let [challengeTasks, userTasks] = await Q.all([
     // Find original challenge tasks
     Tasks.Task.find({
       userId: {$exists: false},
@@ -96,43 +77,112 @@ schema.methods.syncToUser = function syncChallengeToUser (user) {
       userId: user._id,
       'challenge.id': challenge._id,
     }).exec(),
-  ])
-  .then(results => {
-    let challengeTasks = results[0];
-    let userTasks = results[1];
-    let toSave = []; // An array of things to save
+  ]);
 
-    challengeTasks.forEach(chalTask => {
-      let matchingTask = _.find(userTasks, userTask => userTask.challenge.taskId === chalTask._id);
+  let toSave = []; // An array of things to save
 
-      if (!matchingTask) { // If the task is new, create it
-        matchingTask = new Tasks[chalTask.type](Tasks.Task.sanitizeCreate(_syncableAttrs(chalTask)));
-        matchingTask.challenge = {taskId: chalTask._id, id: challenge._id};
-        matchingTask.userId = user._id;
-        user.tasksOrder[`${chalTask.type}s`].push(matchingTask._id);
-      } else {
-        _.merge(matchingTask, _syncableAttrs(chalTask));
-        // Make sure the task is in user.tasksOrder TODO necessary?
-        let orderList = user.tasksOrder[`${chalTask.type}s`];
-        if (orderList.indexOf(matchingTask._id) === -1 && (matchingTask.type !== 'todo' || !matchingTask.completed)) orderList.push(matchingTask._id);
-      }
+  challengeTasks.forEach(chalTask => {
+    let matchingTask = _.find(userTasks, userTask => userTask.challenge.taskId === chalTask._id);
 
-      if (!matchingTask.notes) matchingTask.notes = chalTask.notes; // don't override the notes, but provide it if not provided
-      if (matchingTask.tags.indexOf(challenge._id) === -1) matchingTask.tags.push(challenge._id); // add tag if missing
-      toSave.push(matchingTask.save());
-    });
+    if (!matchingTask) { // If the task is new, create it
+      matchingTask = new Tasks[chalTask.type](Tasks.Task.sanitizeCreate(_syncableAttrs(chalTask)));
+      matchingTask.challenge = {taskId: chalTask._id, id: challenge._id};
+      matchingTask.userId = user._id;
+      user.tasksOrder[`${chalTask.type}s`].push(matchingTask._id);
+    } else {
+      _.merge(matchingTask, _syncableAttrs(chalTask));
+      // Make sure the task is in user.tasksOrder TODO necessary?
+      let orderList = user.tasksOrder[`${chalTask.type}s`];
+      if (orderList.indexOf(matchingTask._id) === -1 && (matchingTask.type !== 'todo' || !matchingTask.completed)) orderList.push(matchingTask._id);
+    }
 
-    // Flag deleted tasks as "broken"
-    userTasks.forEach(userTask => {
-      if (!_.find(challengeTasks, chalTask => chalTask._id === userTask.challenge.taskId)) {
-        userTask.challenge.broken = 'TASK_DELETED';
-        toSave.push(userTask.save());
-      }
-    });
-
-    toSave.push(user.save());
-    return Q.all(toSave);
+    if (!matchingTask.notes) matchingTask.notes = chalTask.notes; // don't override the notes, but provide it if not provided
+    if (matchingTask.tags.indexOf(challenge._id) === -1) matchingTask.tags.push(challenge._id); // add tag if missing
+    toSave.push(matchingTask.save());
   });
+
+  // Flag deleted tasks as "broken"
+  userTasks.forEach(userTask => {
+    if (!_.find(challengeTasks, chalTask => chalTask._id === userTask.challenge.taskId)) {
+      userTask.challenge.broken = 'TASK_DELETED';
+      toSave.push(userTask.save());
+    }
+  });
+
+  toSave.push(user.save());
+  return Q.all(toSave);
+};
+
+async function _fetchMembersIds (challengeId) {
+  return (await User.find({challenges: {$in: [challengeId]}}).select('_id').lean().exec()).map(member => member._id);
+}
+
+// Add a new task to challenge members
+schema.methods.addTasks = async function challengeAddTasks (tasks) {
+  let challenge = this;
+  let membersIds = await _fetchMembersIds(challenge._id);
+
+  // Sync each user sequentially
+  for (let memberId of membersIds) {
+    let updateTasksOrderQ = {$push: {}};
+    let toSave = [];
+
+    // TODO eslint complaints about ahving a function inside a loop -> make sure it works
+    tasks.forEach(chalTask => { // eslint-disable-line no-loop-func
+      let userTask = new Tasks[chalTask.type](Tasks.Task.sanitizeCreate(_syncableAttrs(chalTask)));
+      userTask.challenge = {taskId: chalTask._id, id: challenge._id};
+      userTask.userId = memberId;
+
+      let tasksOrderList = updateTasksOrderQ.$push[`tasksOrder.${chalTask.type}s`];
+      if (!tasksOrderList) {
+        updateTasksOrderQ.$push[`tasksOrder.${chalTask.type}s`] = {
+          $position: 0, // unshift
+          $each: [userTask._id],
+        };
+      } else {
+        tasksOrderList.$each.unshift(userTask._id);
+      }
+
+      toSave.push(userTask);
+    });
+
+    // Update the user
+    toSave.unshift(User.update({_id: memberId}, updateTasksOrderQ).exec());
+    await Q.all(toSave); // eslint-disable-line babel/no-await-in-loop
+  }
+};
+
+// Sync updated task to challenge members
+schema.methods.updateTask = async function challengeUpdateTask (task) {
+  let challenge = this;
+
+  let updateCmd = {$set: {}};
+
+  _syncableAttrs(task).forEach((value, key) => {
+    updateCmd.$set[key] = value;
+  });
+
+  // TODO reveiw
+  // Updating instead of loading and saving for performances, risks becoming a problem if we introduce more complexity in tasks
+  await Tasks.Task.update({
+    userId: {$exists: true},
+    'challenge.id': challenge.id,
+    'challenge.taskId': task._id,
+  }, updateCmd, {multi: true}).exec();
+};
+
+// Remove a task from challenge members
+schema.methods.removeTask = async function challengeRemoveTask (task) {
+  let challenge = this;
+
+  // Set the task as broken
+  await Tasks.Task.update({
+    userId: {$exists: true},
+    'challenge.id': challenge.id,
+    'challenge.taskId': task._id,
+  }, {
+    $set: {'challenge.broken': 'TASK_DELETED'}, // TODO what about updatedAt?
+  }, {multi: true}).exec();
 };
 
 export let model = mongoose.model('Challenge', schema);
diff --git a/website/src/models/group.js b/website/src/models/group.js
index 3efde03dcc..94072bfb79 100644
--- a/website/src/models/group.js
+++ b/website/src/models/group.js
@@ -438,7 +438,7 @@ schema.statics.bossQuest = function bossQuest (user, progress) {
 
 // Remove user from this group
 // TODO this is highly inefficient
-schema.methods.leave = function leaveGroup (user, keep = 'keep-all') {
+schema.methods.leave = function leaveGroup (user, keep) {
   let group = this;
 
   return Q.all([
@@ -454,12 +454,12 @@ schema.methods.leave = function leaveGroup (user, keep = 'keep-all') {
         {_id: {$in: _.pluck(challenges, '_id')}},
         {$pull: {members: user._id}},
         {multi: true}
-      ).then(() => challenges); // pass `challenges` above to next promise TODO ok to return a non-promise?
+      ).then(() => challenges); // pass `challenges` above to next promise
     }).then(challenges => {
       return Q.all(challenges.map(chal => {
         let i = user.challenges.indexOf(chal._id);
         if (i !== -1) user.challenges.splice(i, 1);
-        return user.unlink({cid: chal._id, keep});
+        return user.unlinkChallengeTasks(chal._id, keep);
       }));
     }),
 
diff --git a/website/src/models/task.js b/website/src/models/task.js
index b31676da10..3fd574af93 100644
--- a/website/src/models/task.js
+++ b/website/src/models/task.js
@@ -28,7 +28,7 @@ export let TaskSchema = new Schema({
 
   challenge: {
     id: {type: String, ref: 'Challenge', validate: [validator.isUUID, 'Invalid uuid.']}, // When set (and userId not set) it's the original task
-    taskId: {type: String, ref: 'Task', validate: [validator.isUUID, 'Invalid uuid.']}, // When not set but challenge.id defined it's the original task
+    taskId: {type: String, ref: 'Task', validate: [validator.isUUID, 'Invalid uuid.']}, // When not set but challenge.id defined it's the original task TODO unique index?
     broken: {type: String, enum: ['CHALLENGE_DELETED', 'TASK_DELETED', 'UNSUBSCRIBED', 'CHALLENGE_CLOSED']},
     winner: String, // user.profile.name TODO necessary?
   },
diff --git a/website/src/models/user.js b/website/src/models/user.js
index ba30cbad93..fcad88c5a6 100644
--- a/website/src/models/user.js
+++ b/website/src/models/user.js
@@ -651,40 +651,34 @@ schema.methods.isSubscribed = function isSubscribed () {
   return !!this.purchased.plan.customerId; // eslint-disable-line no-implicit-coercion
 };
 
-schema.methods.unlink = function unlink (options, cb) {
-  let cid = options.cid;
-  let keep = options.keep;
-  let tid = options.tid;
+// Unlink challenges tasks from user
+schema.methods.unlinkChallengeTasks = async function unlinkChallengeTasks (challengeId, keep) {
+  let user = this;
+  let findQuery = {
+    userId: user._id,
+    'challenge.id': challengeId,
+  };
 
-  if (!cid) {
-    return cb('Could not remove challenge tasks. Please delete them manually.');
-  }
-
-  let self = this;
-
-  if (keep === 'keep') {
-    self.tasks[tid].challenge = {};
-  } else if (keep === 'remove') {
-    self.ops.deleteTask({params: {id: tid}}, () => {});
-  } else if (keep === 'keep-all') {
-    _.each(self.tasks, (t) => {
-      if (t.challenge && t.challenge.id === cid) {
-        t.challenge = {};
+  if (keep === 'keep-all') {
+    await Tasks.Task.update(findQuery, {
+      $set: {challenge: {}}, // TODO what about updatedAt?
+    }, {multi: true}).exec();
+  } else { // keep = 'remove-all'
+    let tasks = Tasks.Task.find(findQuery).select('_id type completed').exec();
+    tasks = tasks.map(task => {
+      // Remove task from user.tasksOrder and delete them
+      if (task.type !== 'todo' || !task.completed) {
+        let list = user.tasksOrder[`${task.type}s`];
+        let index = list.indexOf(task._id);
+        if (index !== -1) list.splice(index, 1);
       }
-    });
-  } else if (keep === 'remove-all') {
-    _.each(self.tasks, (t) => {
-      if (t.challenge && t.challenge.id === cid) {
-        this.ops.deleteTask({params: {id: tid}}, () => {});
-      }
-    });
-  }
 
-  self.markModified('habits');
-  self.markModified('dailys');
-  self.markModified('todos');
-  self.markModified('rewards');
-  self.save(cb);
+      return task.remove();
+    });
+
+    tasks.push(user.save());
+    await Q.all(tasks);
+  }
 };
 
 export let model = mongoose.model('User', schema);