diff --git a/common/locales/en/api-v3.json b/common/locales/en/api-v3.json
index a9c0a0fb2d..73fbcca279 100644
--- a/common/locales/en/api-v3.json
+++ b/common/locales/en/api-v3.json
@@ -128,5 +128,13 @@
   "privateMessageGiftSubscriptionMessage": "<%= numberOfMonths %> months of subscription! ",
   "cannotSendGemsToYourself": "Cannot send gems to yourself. Try a subscription instead.",
   "notEnoughGemsToSend": "Amount must be within 0 and your current number of gems.",
-  "mustPurchaseToSet": "Must purchase <%= val %> to set it on <%= key %>."
+  "mustPurchaseToSet": "Must purchase <%= val %> to set it on <%= key %>.",
+  "typeRequired": "Type is required",
+  "keyRequired": "Key is required",
+  "mustSubscribeToPurchaseGems": "Must subscribe to purchase gems with GP",
+  "reachedGoldToGemCap": "You've reached the Gold=>Gem conversion cap <%= convCap %> for this month. We have this to prevent abuse / farming. The cap will reset within the first three days of next month.",
+  "notAccteptedType": "Type must be in [eggs, hatchingPotions, food, quests, gear]",
+  "contentKeyNotFound": "Key not found for Content <%= type %>",
+  "plusOneGem": "+1 Gem",
+  "purchased": "You purchsed a <%= key %> <%= type %>"
 }
diff --git a/common/script/index.js b/common/script/index.js
index 7f9736044d..8edc435cae 100644
--- a/common/script/index.js
+++ b/common/script/index.js
@@ -114,6 +114,7 @@ import feed from './ops/feed';
 import equip from './ops/equip';
 import changeClass from './ops/changeClass';
 import disableClasses from './ops/disableClasses';
+import purchase from './ops/purchase';
 
 api.ops = {
   scoreTask,
@@ -129,6 +130,7 @@ api.ops = {
   equip,
   changeClass,
   disableClasses,
+  purchase,
 };
 
 import handleTwoHanded from './fns/handleTwoHanded';
diff --git a/common/script/ops/purchase.js b/common/script/ops/purchase.js
index d4d0f78816..abb7992994 100644
--- a/common/script/ops/purchase.js
+++ b/common/script/ops/purchase.js
@@ -3,105 +3,126 @@ import i18n from '../i18n';
 import _ from 'lodash';
 import splitWhitespace from '../libs/splitWhitespace';
 import planGemLimits from '../libs/planGemLimits';
+import {
+  NotFound,
+  NotAuthorized,
+  BadRequest,
+} from '../libs/errors';
+
+module.exports = function purchase (user, req = {}, analytics) {
+  let type = _.get(req.params, 'type');
+  let key = _.get(req.params, 'key');
+  let item;
+  let price;
+
+  if (!type) {
+    throw new BadRequest(i18n.t('typeRequired', req.language));
+  }
+
+  if (!key) {
+    throw new BadRequest(i18n.t('keyRequired', req.language));
+  }
 
-module.exports = function(user, req, cb, analytics) {
-  var analyticsData, convCap, convRate, item, key, price, ref, ref1, ref2, ref3, type;
-  ref = req.params, type = ref.type, key = ref.key;
   if (type === 'gems' && key === 'gem') {
-    ref1 = planGemLimits, convRate = ref1.convRate, convCap = ref1.convCap;
+    let convRate = planGemLimits.convRate;
+    let convCap = planGemLimits.convCap;
     convCap += user.purchased.plan.consecutive.gemCapExtra;
-    if (!((ref2 = user.purchased) != null ? (ref3 = ref2.plan) != null ? ref3.customerId : void 0 : void 0)) {
-      return typeof cb === "function" ? cb({
-        code: 401,
-        message: "Must subscribe to purchase gems with GP"
-      }, req) : void 0;
+
+    if (!user.purchased || !user.purchased.plan || !user.purchased.plan.customerId) {
+      throw new NotAuthorized(i18n.t('mustSubscribeToPurchaseGems', req.language));
     }
-    if (!(user.stats.gp >= convRate)) {
-      return typeof cb === "function" ? cb({
-        code: 401,
-        message: "Not enough Gold"
-      }) : void 0;
+
+    if (user.stats.gp < convRate) {
+      throw new NotAuthorized(i18n.t('messageNotEnoughGold', req.language));
     }
+
     if (user.purchased.plan.gemsBought >= convCap) {
-      return typeof cb === "function" ? cb({
-        code: 401,
-        message: "You've reached the Gold=>Gem conversion cap (" + convCap + ") for this month. We have this to prevent abuse / farming. The cap will reset within the first three days of next month."
-      }) : void 0;
+      throw new NotAuthorized(i18n.t('reachedGoldToGemCap', {convCap}, req.language));
     }
-    user.balance += .25;
+
+    user.balance += 0.25;
     user.purchased.plan.gemsBought++;
     user.stats.gp -= convRate;
-    analyticsData = {
-      uuid: user._id,
-      itemKey: key,
-      acquireMethod: 'Gold',
-      goldCost: convRate,
-      category: 'behavior'
-    };
-    if (analytics != null) {
-      analytics.track('purchase gems', analyticsData);
+
+    if (analytics) {
+      analytics.track('purchase gems', {
+        uuid: user._id,
+        itemKey: key,
+        acquireMethod: 'Gold',
+        goldCost: convRate,
+        category: 'behavior',
+      });
     }
-    return typeof cb === "function" ? cb({
-      code: 200,
-      message: "+1 Gem"
-    }, _.pick(user, splitWhitespace('stats balance'))) : void 0;
+
+    let response = {
+      data: _.pick(user, splitWhitespace('stats balance')),
+      message: i18n.t('plusOneGem'),
+    };
+
+    return response;
   }
-  if (type !== 'eggs' && type !== 'hatchingPotions' && type !== 'food' && type !== 'quests' && type !== 'gear') {
-    return typeof cb === "function" ? cb({
-      code: 404,
-      message: ":type must be in [eggs,hatchingPotions,food,quests,gear]"
-    }, req) : void 0;
+
+  let acceptedTypes = ['eggs', 'hatchingPotions', 'food', 'quests', 'gear'];
+  if (acceptedTypes.indexOf(type) === -1) {
+    throw new NotFound(i18n.t('notAccteptedType', req.language));
   }
+
   if (type === 'gear') {
     item = content.gear.flat[key];
-    if (user.items.gear.owned[key]) {
-      return typeof cb === "function" ? cb({
-        code: 401,
-        message: i18n.t('alreadyHave', req.language)
-      }) : void 0;
+
+    if (!item) {
+      throw new NotFound(i18n.t('contentKeyNotFound', {type}, req.language));
     }
+
+    if (user.items.gear.owned[key]) {
+      throw new NotAuthorized(i18n.t('alreadyHave', req.language));
+    }
+
     price = (item.twoHanded || item.gearSet === 'animal' ? 2 : 1) / 4;
   } else {
     item = content[type][key];
+
+    if (!item) {
+      throw new NotFound(i18n.t('contentKeyNotFound', {type}, req.language));
+    }
+
     price = item.value / 4;
   }
-  if (!item) {
-    return typeof cb === "function" ? cb({
-      code: 404,
-      message: ":key not found for Content." + type
-    }, req) : void 0;
-  }
+
   if (!item.canBuy(user)) {
-    return typeof cb === "function" ? cb({
-      code: 403,
-      message: i18n.t('messageNotAvailable', req.language)
-    }) : void 0;
+    throw new NotAuthorized(i18n.t('messageNotAvailable', req.language));
   }
-  if ((user.balance < price) || !user.balance) {
-    return typeof cb === "function" ? cb({
-      code: 403,
-      message: i18n.t('notEnoughGems', req.language)
-    }) : void 0;
+
+  if (!user.balance || user.balance < price) {
+    throw new NotAuthorized(i18n.t('notEnoughGems', req.language));
   }
+
   user.balance -= price;
+
   if (type === 'gear') {
     user.items.gear.owned[key] = true;
   } else {
-    if (!(user.items[type][key] > 0)) {
+    if (!user.items[type][key] || user.items[type][key] < 0) {
       user.items[type][key] = 0;
     }
     user.items[type][key]++;
   }
-  analyticsData = {
-    uuid: user._id,
-    itemKey: key,
-    itemType: 'Market',
-    acquireMethod: 'Gems',
-    gemCost: item.value,
-    category: 'behavior'
-  };
-  if (analytics != null) {
-    analytics.track('acquire item', analyticsData);
+
+  if (analytics) {
+    analytics.track('acquire item', {
+      uuid: user._id,
+      itemKey: key,
+      itemType: 'Market',
+      acquireMethod: 'Gems',
+      gemCost: item.value,
+      category: 'behavior',
+    });
   }
-  return typeof cb === "function" ? cb(null, _.pick(user, splitWhitespace('items balance'))) : void 0;
+
+  let response = {
+    data: _.pick(user, splitWhitespace('items balance')),
+    message: i18n.t('purchased', {type, key}),
+  };
+
+  return response;
 };
diff --git a/tasks/gulp-eslint.js b/tasks/gulp-eslint.js
index 6fb94f6d2b..6208dfbeb5 100644
--- a/tasks/gulp-eslint.js
+++ b/tasks/gulp-eslint.js
@@ -30,7 +30,6 @@ const COMMON_FILES = [
   '!./common/script/ops/getTags.js',
   '!./common/script/ops/hourglassPurchase.js',
   '!./common/script/ops/openMysteryItem.js',
-  '!./common/script/ops/purchase.js',
   '!./common/script/ops/readCard.js',
   '!./common/script/ops/rebirth.js',
   '!./common/script/ops/releaseBoth.js',
diff --git a/test/api/v3/integration/user/POST-user_purchase.test.js b/test/api/v3/integration/user/POST-user_purchase.test.js
new file mode 100644
index 0000000000..6afaa14cb6
--- /dev/null
+++ b/test/api/v3/integration/user/POST-user_purchase.test.js
@@ -0,0 +1,35 @@
+import {
+  generateUser,
+  translate as t,
+} from '../../../../helpers/api-integration/v3';
+
+describe('POST /user/purchase/:type/:key', () => {
+  let user;
+  let type = 'hatchingPotions';
+  let key = 'Base';
+
+  beforeEach(async () => {
+    user = await generateUser({
+      balance: 40,
+    });
+  });
+
+  // More tests in common code unit tests
+
+  it('returns an error when key is not provided', async () => {
+    await expect(user.post(`/user/purchase/gems/gem`))
+      .to.eventually.be.rejected.and.eql({
+        code: 401,
+        error: 'NotAuthorized',
+        message: t('mustSubscribeToPurchaseGems'),
+      });
+  });
+
+  it('purchases a gem item', async () => {
+    let res = await user.post(`/user/purchase/${type}/${key}`);
+    await user.sync();
+
+    expect(res.message).to.equal(t('purchased', {type, key}));
+    expect(user.items[type][key]).to.equal(1);
+  });
+});
diff --git a/test/common/ops/purchase.js b/test/common/ops/purchase.js
new file mode 100644
index 0000000000..557ee006cf
--- /dev/null
+++ b/test/common/ops/purchase.js
@@ -0,0 +1,199 @@
+import purchase from '../../../common/script/ops/purchase';
+import planGemLimits from '../../../common/script/libs/planGemLimits';
+import {
+  BadRequest,
+  NotAuthorized,
+  NotFound,
+} from '../../../common/script/libs/errors';
+import i18n from '../../../common/script/i18n';
+import {
+  generateUser,
+} from '../../helpers/common.helper';
+
+describe('shared.ops.feed', () => {
+  let user;
+  let goldPoints = 40;
+  let gemsBought = 40;
+
+  before(() => {
+    user = generateUser({'stats.class': 'rogue'});
+  });
+
+  context('failure conditions', () => {
+    it('returns an error when type is not provided', (done) => {
+      try {
+        purchase(user, {params: {}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(BadRequest);
+        expect(err.message).to.equal(i18n.t('typeRequired'));
+        done();
+      }
+    });
+
+    it('returns an error when key is not provided', (done) => {
+      try {
+        purchase(user, {params: {type: 'gems'}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(BadRequest);
+        expect(err.message).to.equal(i18n.t('keyRequired'));
+        done();
+      }
+    });
+
+    it('prevents unsubscribed user from buying gems', (done) => {
+      try {
+        purchase(user, {params: {type: 'gems', key: 'gem'}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(NotAuthorized);
+        expect(err.message).to.equal(i18n.t('mustSubscribeToPurchaseGems'));
+        done();
+      }
+    });
+
+    it('prevents user with not enough gold from buying gems', (done) => {
+      user.purchased.plan.customerId = 'customer-id';
+
+      try {
+        purchase(user, {params: {type: 'gems', key: 'gem'}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(NotAuthorized);
+        expect(err.message).to.equal(i18n.t('messageNotEnoughGold'));
+        done();
+      }
+    });
+
+    it('prevents user that have reached the conversion cap from buying gems', (done) => {
+      user.stats.gp = goldPoints;
+      user.purchased.plan.gemsBought = gemsBought;
+
+      try {
+        purchase(user, {params: {type: 'gems', key: 'gem'}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(NotAuthorized);
+        expect(err.message).to.equal(i18n.t('reachedGoldToGemCap', {convCap: planGemLimits.convCap}));
+        done();
+      }
+    });
+
+    it('returns error when unknown type is provided', (done) => {
+      try {
+        purchase(user, {params: {type: 'randomType', key: 'gem'}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(NotFound);
+        expect(err.message).to.equal(i18n.t('notAccteptedType'));
+        done();
+      }
+    });
+
+    it('returns error when user attempts to purchase a piece of gear they own', (done) => {
+      user.items.gear.owned['shield_rogue_1'] = true; // eslint-disable-line dot-notation
+
+      try {
+        purchase(user, {params: {type: 'gear', key: 'shield_rogue_1'}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(NotAuthorized);
+        expect(err.message).to.equal(i18n.t('alreadyHave'));
+        done();
+      }
+    });
+
+    it('returns error when unknown item is requested', (done) => {
+      try {
+        purchase(user, {params: {type: 'gear', key: 'randomKey'}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(NotFound);
+        expect(err.message).to.equal(i18n.t('contentKeyNotFound', {type: 'gear'}));
+        done();
+      }
+    });
+
+    it('returns error when user does not have permission to buy an item', (done) => {
+      try {
+        purchase(user, {params: {type: 'gear', key: 'eyewear_mystery_301405'}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(NotAuthorized);
+        expect(err.message).to.equal(i18n.t('messageNotAvailable'));
+        done();
+      }
+    });
+
+    it('returns error when user does not have enough gems to buy an item', (done) => {
+      try {
+        purchase(user, {params: {type: 'gear', key: 'headAccessory_special_wolfEars'}});
+      } catch (err) {
+        expect(err).to.be.an.instanceof(NotAuthorized);
+        expect(err.message).to.equal(i18n.t('notEnoughGems'));
+        done();
+      }
+    });
+  });
+
+  context('successful feeding', () => {
+    let userGemAmount = 10;
+
+    before(() => {
+      user.balance = userGemAmount;
+      user.stats.gp = goldPoints;
+      user.purchased.plan.gemsBought = 0;
+    });
+
+    it('purchases gems', () => {
+      let purchaseResponse = purchase(user, {params: {type: 'gems', key: 'gem'}});
+
+      expect(purchaseResponse.message).to.equal(i18n.t('plusOneGem'));
+      expect(user.balance).to.equal(userGemAmount + 0.25);
+      expect(user.purchased.plan.gemsBought).to.equal(1);
+      expect(user.stats.gp).to.equal(goldPoints - planGemLimits.convRate);
+    });
+
+    it('purchases eggs', () => {
+      let type = 'eggs';
+      let key = 'Wolf';
+
+      let purchaseResponse = purchase(user, {params: {type, key}});
+
+      expect(purchaseResponse.message).to.equal(i18n.t('purchased', {type, key}));
+      expect(user.items[type][key]).to.equal(1);
+    });
+
+    it('purchases hatchingPotions', () => {
+      let type = 'hatchingPotions';
+      let key = 'Base';
+
+      let purchaseResponse = purchase(user, {params: {type, key}});
+
+      expect(purchaseResponse.message).to.equal(i18n.t('purchased', {type, key}));
+      expect(user.items[type][key]).to.equal(1);
+    });
+
+    it('purchases food', () => {
+      let type = 'food';
+      let key = 'Meat';
+
+      let purchaseResponse = purchase(user, {params: {type, key}});
+
+      expect(purchaseResponse.message).to.equal(i18n.t('purchased', {type, key}));
+      expect(user.items[type][key]).to.equal(1);
+    });
+
+    it('purchases quests', () => {
+      let type = 'quests';
+      let key = 'gryphon';
+
+      let purchaseResponse = purchase(user, {params: {type, key}});
+
+      expect(purchaseResponse.message).to.equal(i18n.t('purchased', {type, key}));
+      expect(user.items[type][key]).to.equal(1);
+    });
+
+    it('purchases gear', () => {
+      let type = 'gear';
+      let key = 'headAccessory_special_tigerEars';
+
+      let purchaseResponse = purchase(user, {params: {type, key}});
+
+      expect(purchaseResponse.message).to.equal(i18n.t('purchased', {type, key}));
+      expect(user.items.gear.owned[key]).to.be.true;
+    });
+  });
+});
diff --git a/website/src/controllers/api-v3/user.js b/website/src/controllers/api-v3/user.js
index 147f1552c9..8dcf87cad9 100644
--- a/website/src/controllers/api-v3/user.js
+++ b/website/src/controllers/api-v3/user.js
@@ -676,4 +676,27 @@ api.disableClasses = {
   },
 };
 
+/**
+* @api {post} /user/purchase/:type/:key Purchase Gem Items.
+* @apiVersion 3.0.0
+* @apiName UserPurchase
+* @apiGroup User
+*
+* @apiParam {string} type Type of item to purchase
+* @apiParam {string} key Item's key
+*
+* @apiSuccess {Object} data `items balance`
+*/
+api.purchase = {
+  method: 'POST',
+  middlewares: [authWithHeaders(), cron],
+  url: '/user/purchase/:type/:key',
+  async handler (req, res) {
+    let user = res.locals.user;
+    let purchaseResponse = common.ops.purchase(user, req, res.analytics);
+    await user.save();
+    res.respond(200, purchaseResponse);
+  },
+};
+
 module.exports = api;