diff --git a/test/api/v3/integration/chat/POST-chat_seen.test.js b/test/api/v3/integration/chat/POST-chat_seen.test.js
new file mode 100644
index 00000000000..9f90ca3296a
--- /dev/null
+++ b/test/api/v3/integration/chat/POST-chat_seen.test.js
@@ -0,0 +1,67 @@
+import {
+  createAndPopulateGroup,
+} from '../../../../helpers/api-v3-integration.helper';
+
+describe('POST /groups/:id/chat/seen', () => {
+  context('Guild', () => {
+    let guild, guildLeader, guildMember, guildMessage;
+
+    before(async () => {
+      let { group, groupLeader, members } = await createAndPopulateGroup({
+        groupDetails: {
+          type: 'guild',
+          privacy: 'public',
+        },
+        members: 1,
+      });
+
+      guild = group;
+      guildLeader = groupLeader;
+      guildMember = members[0];
+
+      guildMessage = await guildLeader.post(`/groups/${guild._id}/chat`, { message: 'Some guild message' });
+      guildMessage = guildMessage.message;
+    });
+
+    it('clears new messages for a guild', async () => {
+      let user = await guildMember.get('/user');
+
+      await guildMember.post(`/groups/${guild._id}/chat/seen`);
+
+      let guildThatHasSeenChat = await guildMember.get('/user');
+
+      expect(guildThatHasSeenChat.newMessages).to.be.empty;
+    });
+  });
+
+  context('Party', () => {
+    let party, partyLeader, partyMember, partyMessage;
+
+    before(async () => {
+      let { group, groupLeader, members } = await createAndPopulateGroup({
+        groupDetails: {
+          type: 'party',
+          privacy: 'private',
+        },
+        members: 1,
+      });
+
+      party = group;
+      partyLeader = groupLeader;
+      partyMember = members[0];
+
+      partyMessage = await partyLeader.post(`/groups/${party._id}/chat`, { message: 'Some party message' });
+      partyMessage = partyMessage.message;
+    });
+
+    it('clears new messages for a party', async () => {
+      let user = await partyMember.get('/user');
+
+      await partyMember.post(`/groups/${party._id}/chat/seen`);
+
+      let partyMemberThatHasSeenChat = await partyMember.get('/user');
+
+      expect(partyMemberThatHasSeenChat.newMessages).to.be.empty;
+    });
+  });
+});
diff --git a/website/src/controllers/api-v3/chat.js b/website/src/controllers/api-v3/chat.js
index 212e0644418..bfca7eb3b7f 100644
--- a/website/src/controllers/api-v3/chat.js
+++ b/website/src/controllers/api-v3/chat.js
@@ -105,7 +105,7 @@ api.postChat = {
  * @apiSuccess {Array} chat An array of chat messages
  */
 api.likeChat = {
-  method: 'Post',
+  method: 'POST',
   url: '/groups/:groupId/chat/:chatId/like',
   middlewares: [authWithHeaders(), cron],
   async handler (req, res) {
@@ -152,7 +152,7 @@ api.likeChat = {
  * @apiSuccess {Array} chat An array of chat messages
  */
 api.flagChat = {
-  method: 'Post',
+  method: 'POST',
   url: '/groups/:groupId/chat/:chatId/flag',
   middlewares: [authWithHeaders(), cron],
   async handler (req, res) {
@@ -256,4 +256,40 @@ api.flagChat = {
   },
 };
 
+/**
+ * @api {post} /groups/:groupId/chat/:chatId/seen Seen a group chat message
+ * @apiVersion 3.0.0
+ * @apiName SeenChat
+ * @apiGroup Chat
+ *
+ * @apiParam {groupId} groupId The group _id
+ *
+ * @apiSuccess {None}
+ */
+api.seenChat = {
+  method: 'POST',
+  url: '/groups/:groupId/chat/seen',
+  middlewares: [authWithHeaders(), cron],
+  async handler (req, res) {
+    let user = res.locals.user;
+    let groupId = req.params.groupId;
+
+    req.checkParams('groupId', res.t('groupIdRequired')).notEmpty();
+
+    let validationErrors = req.validationErrors();
+    if (validationErrors) throw validationErrors;
+
+    let group = await Group.getGroup({user, groupId});
+    if (!group) throw new NotFound(res.t('groupNotFound'));
+
+    // Skip the auth step, we want this to be fast. If !found with uuid/token, then it just doesn't save
+    let update = { $unset: {} };
+
+    update.$unset[`newMessages.${groupId}`] = '';
+    await User.update({_id: user._id}, update).exec();
+
+    res.respond(200);
+  },
+};
+
 export default api;
diff --git a/website/src/models/group.js b/website/src/models/group.js
index af592bb332f..246a2f06254 100644
--- a/website/src/models/group.js
+++ b/website/src/models/group.js
@@ -204,9 +204,17 @@ schema.methods.sendChat = function sendChat (message, user) {
     // var profileNames = [] // get usernames from regex of @xyz. how to handle space-delimited profile names?
     // User.update({'profile.name':{$in:profileNames}},lastSeenUpdate,{multi:true}).exec();
   } else {
-    User.update({
-      _id: {$in: this.members, $ne: user ? user._id : ''},
-    }, lastSeenUpdate, {multi: true}).exec();
+    let query = {};
+
+    if (this.type === 'party') {
+      query['party._id'] = this._id;
+    } else {
+      query.guilds = this._id;
+    }
+
+    query._id = { $ne: user ? user._id : ''};
+
+    User.update(query, lastSeenUpdate, {multi: true}).exec();
   }
 };