diff --git a/common/locales/en/api-v3.json b/common/locales/en/api-v3.json
index a4fd69f0a3..7c2f5c1001 100644
--- a/common/locales/en/api-v3.json
+++ b/common/locales/en/api-v3.json
@@ -154,5 +154,8 @@
   "mountsReleased": "Mounts released",
   "typeNotSellable": "Type is not sellable. Must be one of the following <%= acceptedTypes %>",
   "userItemsKeyNotFound": "Key not found for user.items <%= type %>",
-  "sold": "You sold a <%= key %> <%= type %>"
+  "sold": "You sold a <%= key %> <%= type %>",
+  "pathRequired": "Path string is required",
+  "unlocked": "Items have been unlocked",
+  "alreadyUnlocked": "Item already unlocked"
 }
diff --git a/common/script/index.js b/common/script/index.js
index c55ac24c9f..3b4c5769cd 100644
--- a/common/script/index.js
+++ b/common/script/index.js
@@ -122,6 +122,7 @@ import releasePets from './ops/releasePets';
 import releaseBoth from './ops/releaseBoth';
 import releaseMounts from './ops/releaseMounts';
 import sell from './ops/sell';
+import unlock from './ops/unlock';
 
 api.ops = {
   scoreTask,
@@ -145,6 +146,7 @@ api.ops = {
   releaseBoth,
   releaseMounts,
   sell,
+  unlock,
 };
 
 import handleTwoHanded from './fns/handleTwoHanded';
diff --git a/common/script/ops/unlock.js b/common/script/ops/unlock.js
index c53a5997ec..bbd3cb0e39 100644
--- a/common/script/ops/unlock.js
+++ b/common/script/ops/unlock.js
@@ -1,63 +1,85 @@
 import i18n from '../i18n';
 import _ from 'lodash';
 import splitWhitespace from '../libs/splitWhitespace';
+import dotSet from '../libs/dotSet';
+import {
+  NotAuthorized,
+  BadRequest,
+} from '../libs/errors';
 
-module.exports = function(user, req, cb, analytics) {
-  var alreadyOwns, analyticsData, cost, fullSet, k, path, split, v;
-  path = req.query.path;
-  fullSet = ~path.indexOf(",");
-  cost = ~path.indexOf('background.') ? fullSet ? 3.75 : 1.75 : fullSet ? 1.25 : 0.5;
-  alreadyOwns = !fullSet && user.fns.dotGet("purchased." + path) === true;
-  if ((user.balance < cost || !user.balance) && !alreadyOwns) {
-    return typeof cb === "function" ? cb({
-      code: 401,
-      message: i18n.t('notEnoughGems', req.language)
-    }) : void 0;
+module.exports = function unlock (user, req = {}, analytics) {
+  let path = _.get(req.query, 'path');
+
+  if (!path) {
+    throw new BadRequest(i18n.t('pathRequired', req.language));
   }
-  if (fullSet) {
-    _.each(path.split(","), function(p) {
-      if (~path.indexOf('gear.')) {
-        user.fns.dotSet("" + p, true);
-        true;
-      } else {
 
+  let isFullSet = path.indexOf(',') !== -1;
+  let cost;
+  let isBackground = path.indexOf('background.') !== -1;
+
+  if (isBackground && isFullSet) {
+    cost = 3.75;
+  } else if (isBackground) {
+    cost = 1.75;
+  } else if (isFullSet) {
+    cost = 1.25;
+  } else {
+    cost = 0.5;
+  }
+
+  let alreadyOwns = !isFullSet && user.fns.dotGet(`purchased.${path}`) === true;
+
+  if ((!user.balance || user.balance < cost) && !alreadyOwns) {
+    throw new NotAuthorized(i18n.t('notEnoughGems', req.language));
+  }
+
+  if (isFullSet) {
+    _.each(path.split(','), function markItemsAsPurchased (pathPart) {
+      if (path.indexOf('gear.') !== -1) {
+        dotSet(user, pathPart, true);
+        return true;
       }
-      user.fns.dotSet("purchased." + p, true);
+
+      dotSet(user, `purchased.${pathPart}`, true);
       return true;
     });
   } else {
     if (alreadyOwns) {
-      split = path.split('.');
-      v = split.pop();
-      k = split.join('.');
-      if (k === 'background' && v === user.preferences.background) {
-        v = '';
+      let split = path.split('.');
+      let value = split.pop();
+      let key = split.join('.');
+      if (key === 'background' && value === user.preferences.background) {
+        value = '';
       }
-      user.fns.dotSet("preferences." + k, v);
-      return typeof cb === "function" ? cb(null, req) : void 0;
+      dotSet(user, `preferences.${key}`, value);
+
+      throw new NotAuthorized(i18n.t('alreadyUnlocked', req.language));
     }
-    user.fns.dotSet("purchased." + path, true);
+    dotSet(user, `purchased.${path}`, true);
   }
+
+  if (path.indexOf('gear.') === -1) {
+    user.markModified('purchased');
+  }
+
   user.balance -= cost;
-  if (~path.indexOf('gear.')) {
-    if (typeof user.markModified === "function") {
-      user.markModified('gear.owned');
-    }
-  } else {
-    if (typeof user.markModified === "function") {
-      user.markModified('purchased');
-    }
+
+  if (analytics) {
+    analytics.track('acquire item', {
+      uuid: user._id,
+      itemKey: path,
+      itemType: 'customization',
+      acquireMethod: 'Gems',
+      gemCost: cost / 0.25,
+      category: 'behavior',
+    });
   }
-  analyticsData = {
-    uuid: user._id,
-    itemKey: path,
-    itemType: 'customization',
-    acquireMethod: 'Gems',
-    gemCost: cost / .25,
-    category: 'behavior'
+
+  let response = {
+    data: _.pick(user, splitWhitespace('purchased preferences items')),
+    message: i18n.t('unlocked'),
   };
-  if (analytics != null) {
-    analytics.track('acquire item', analyticsData);
-  }
-  return typeof cb === "function" ? cb(null, _.pick(user, splitWhitespace('purchased preferences items'))) : void 0;
+
+  return response;
 };
diff --git a/tasks/gulp-eslint.js b/tasks/gulp-eslint.js
index 6ed2b567a9..4376bd07f8 100644
--- a/tasks/gulp-eslint.js
+++ b/tasks/gulp-eslint.js
@@ -32,7 +32,6 @@ const COMMON_FILES = [
   '!./common/script/ops/revive.js',
   '!./common/script/ops/sortTag.js',
   '!./common/script/ops/sortTask.js',
-  '!./common/script/ops/unlock.js',
   '!./common/script/ops/update.js',
   '!./common/script/ops/updateTag.js',
   '!./common/script/ops/updateTask.js',
diff --git a/test/api/v3/integration/user/POST-user_unlock.js b/test/api/v3/integration/user/POST-user_unlock.js
new file mode 100644
index 0000000000..6dbdb3c1b1
--- /dev/null
+++ b/test/api/v3/integration/user/POST-user_unlock.js
@@ -0,0 +1,37 @@
+import {
+  generateUser,
+  translate as t,
+} from '../../../../helpers/api-integration/v3';
+
+describe('POST /user/unlock', () => {
+  let user;
+  let unlockPath = 'shirt.convict,shirt.cross,shirt.fire,shirt.horizon,shirt.ocean,shirt.purple,shirt.rainbow,shirt.redblue,shirt.thunder,shirt.tropical,shirt.zombie';
+  let unlockCost = 1.25;
+  let usersStartingGems = 5;
+
+  beforeEach(async () => {
+    user = await generateUser();
+  });
+
+  it('returns an error when user balance is too low', async () => {
+    await expect(user.post(`/user/unlock?path=${unlockPath}`))
+      .to.eventually.be.rejected.and.to.eql({
+        code: 401,
+        error: 'NotAuthorized',
+        message: t('notEnoughGems'),
+      });
+  });
+
+  // More tests in common code unit tests
+
+  it('reduces a user\'s balance', async () => {
+    await user.update({
+      balance: usersStartingGems,
+    });
+    let response = await user.post(`/user/unlock?path=${unlockPath}`);
+    await user.sync();
+
+    expect(response.message).to.equal(t('unlocked'));
+    expect(user.balance).to.equal(usersStartingGems - unlockCost);
+  });
+});
diff --git a/test/common/ops/unlock.js b/test/common/ops/unlock.js
new file mode 100644
index 0000000000..b7d7bda370
--- /dev/null
+++ b/test/common/ops/unlock.js
@@ -0,0 +1,84 @@
+import unlock from '../../../common/script/ops/unlock';
+import i18n from '../../../common/script/i18n';
+import {
+  generateUser,
+} from '../../helpers/common.helper';
+import {
+  NotAuthorized,
+  BadRequest,
+} from '../../../common/script/libs/errors';
+
+describe('shared.ops.unlock', () => {
+  let user;
+  let unlockPath = 'shirt.convict,shirt.cross,shirt.fire,shirt.horizon,shirt.ocean,shirt.purple,shirt.rainbow,shirt.redblue,shirt.thunder,shirt.tropical,shirt.zombie';
+  let unlockGearSetPath = 'items.gear.owned.headAccessory_special_bearEars,items.gear.owned.headAccessory_special_cactusEars,items.gear.owned.headAccessory_special_foxEars,items.gear.owned.headAccessory_special_lionEars,items.gear.owned.headAccessory_special_pandaEars,items.gear.owned.headAccessory_special_pigEars,items.gear.owned.headAccessory_special_tigerEars,items.gear.owned.headAccessory_special_wolfEars';
+  let backgroundUnlockPath = 'background.giant_florals';
+  let unlockCost = 1.25;
+  let usersStartingGems = 5;
+
+  beforeEach(() => {
+    user = generateUser();
+    user.balance = usersStartingGems;
+  });
+
+  it('returns an error when path is not provided', (done) => {
+    try {
+      unlock(user);
+    } catch (err) {
+      expect(err).to.be.an.instanceof(BadRequest);
+      expect(err.message).to.equal(i18n.t('pathRequired'));
+      done();
+    }
+  });
+
+  it('returns an error when user balance is too low', (done) => {
+    user.balance = 0;
+
+    try {
+      unlock(user, {query: {path: unlockPath}});
+    } catch (err) {
+      expect(err).to.be.an.instanceof(NotAuthorized);
+      expect(err.message).to.equal(i18n.t('notEnoughGems'));
+      done();
+    }
+  });
+
+  it('returns an error when user already owns an item', (done) => {
+    try {
+      unlock(user, {query: {path: backgroundUnlockPath}});
+      unlock(user, {query: {path: backgroundUnlockPath}});
+    } catch (err) {
+      expect(err).to.be.an.instanceof(NotAuthorized);
+      expect(err.message).to.equal(i18n.t('alreadyUnlocked'));
+      done();
+    }
+  });
+
+  it('unlocks a full set', () => {
+    let response = unlock(user, {query: {path: unlockPath}});
+
+    expect(response.message).to.equal(i18n.t('unlocked'));
+    expect(user.purchased.shirt.convict).to.be.true;
+  });
+
+  it('unlocks a full set of gear', () => {
+    let response = unlock(user, {query: {path: unlockGearSetPath}});
+
+    expect(response.message).to.equal(i18n.t('unlocked'));
+    expect(user.items.gear.owned.headAccessory_special_wolfEars).to.be.true;
+  });
+
+  it('unlocks a an item', () => {
+    let response = unlock(user, {query: {path: backgroundUnlockPath}});
+
+    expect(response.message).to.equal(i18n.t('unlocked'));
+    expect(user.purchased.background.giant_florals).to.be.true;
+  });
+
+  it('reduces a user\'s balance', () => {
+    let response = unlock(user, {query: {path: unlockPath}});
+
+    expect(response.message).to.equal(i18n.t('unlocked'));
+    expect(user.balance).to.equal(usersStartingGems - unlockCost);
+  });
+});
diff --git a/website/src/controllers/api-v3/user.js b/website/src/controllers/api-v3/user.js
index c60b2a3eef..bfa4ca8dff 100644
--- a/website/src/controllers/api-v3/user.js
+++ b/website/src/controllers/api-v3/user.js
@@ -848,4 +848,24 @@ api.userSell = {
   },
 };
 
+/*
+* @api {post} /user/unlock Unlocks items by purchase.
+* @apiVersion 3.0.0
+* @apiName UserUnlock
+* @apiGroup User
+*
+* @apiSuccess {Object} data `purchased preferences items`
+*/
+api.userUnlock = {
+  method: 'POST',
+  middlewares: [authWithHeaders(), cron],
+  url: '/user/unlock',
+  async handler (req, res) {
+    let user = res.locals.user;
+    let unlockResponse = common.ops.unlock(user, req);
+    await user.save();
+    res.respond(200, unlockResponse);
+  },
+};
+
 module.exports = api;