diff --git a/app/assets/javascripts/discourse/models/user.js.es6 b/app/assets/javascripts/discourse/models/user.js.es6
index 3e84d0c5501..d4e24f5af83 100644
--- a/app/assets/javascripts/discourse/models/user.js.es6
+++ b/app/assets/javascripts/discourse/models/user.js.es6
@@ -254,7 +254,7 @@ const User = RestModel.extend({
 
     // TODO: We can remove this when migrated fully to rest model.
     this.set('isSaving', true);
-    return ajax(`/users/${this.get('username_lower')}`, {
+    return ajax(`/users/${this.get('username_lower')}.json`, {
       data: data,
       type: 'PUT'
     }).then(result => {
diff --git a/config/routes.rb b/config/routes.rb
index 014d96b0780..cc638f20855 100644
--- a/config/routes.rb
+++ b/config/routes.rb
@@ -327,7 +327,7 @@ Discourse::Application.routes.draw do
 
   get "users/:username.json" => "users#show", constraints: {username: USERNAME_ROUTE_FORMAT}, defaults: {format: :json}
   get "users/:username" => "users#show", as: 'user', constraints: {username: USERNAME_ROUTE_FORMAT}
-  put "users/:username" => "users#update", constraints: {username: USERNAME_ROUTE_FORMAT}
+  put "users/:username" => "users#update", constraints: {username: USERNAME_ROUTE_FORMAT}, defaults: { format: :json }
   get "users/:username/emails" => "users#check_emails", constraints: {username: USERNAME_ROUTE_FORMAT}
   get "users/:username/preferences" => "users#preferences", constraints: {username: USERNAME_ROUTE_FORMAT}, as: :email_preferences
   get "users/:username/preferences/email" => "users_email#index", constraints: {username: USERNAME_ROUTE_FORMAT}
diff --git a/spec/integration/groups_spec.rb b/spec/integration/groups_spec.rb
index cf2f0547777..ddd273d39c0 100644
--- a/spec/integration/groups_spec.rb
+++ b/spec/integration/groups_spec.rb
@@ -4,14 +4,6 @@ describe "Groups" do
   let(:user) { Fabricate(:user) }
   let(:group) { Fabricate(:group, users: [user]) }
 
-  def sign_in(user)
-    password = 'somecomplicatedpassword'
-    user.update!(password: password)
-    Fabricate(:email_token, confirmed: true, user: user)
-    post "/session.json", { login: user.username, password: password }
-    expect(response).to be_success
-  end
-
   describe 'viewing groups' do
     it 'should return the right response' do
       group.update_attributes!(visible: true)
diff --git a/spec/integration/users_spec.rb b/spec/integration/users_spec.rb
new file mode 100644
index 00000000000..aed127a1a1a
--- /dev/null
+++ b/spec/integration/users_spec.rb
@@ -0,0 +1,31 @@
+require 'rails_helper'
+
+RSpec.describe "Users" do
+  let(:user) { Fabricate(:user) }
+
+  describe "updating a user" do
+    before do
+      sign_in(user)
+    end
+
+    it "should be able to update a user" do
+      put "/users/#{user.username}.json", { name: 'test.test' }
+
+      expect(response).to be_success
+      expect(user.reload.name).to eq('test.test')
+    end
+
+    describe 'when username contains a period' do
+      before do
+        user.update!(username: 'test.test')
+      end
+
+      it "should be able to update a user" do
+        put "/users/#{user.username}.json", { name: 'testing123' }
+
+        expect(response).to be_success
+        expect(user.reload.name).to eq('testing123')
+      end
+    end
+  end
+end
diff --git a/spec/rails_helper.rb b/spec/rails_helper.rb
index c1297809c01..478af450ca2 100644
--- a/spec/rails_helper.rb
+++ b/spec/rails_helper.rb
@@ -43,6 +43,7 @@ Spork.prefork do
     config.include Helpers
     config.include MessageBus
     config.include RSpecHtmlMatchers
+    config.include IntegrationHelpers, type: :request
     config.mock_framework = :mocha
     config.order = 'random'
     config.infer_spec_type_from_file_location!
diff --git a/spec/support/integration_helpers.rb b/spec/support/integration_helpers.rb
new file mode 100644
index 00000000000..24331a0761c
--- /dev/null
+++ b/spec/support/integration_helpers.rb
@@ -0,0 +1,9 @@
+module IntegrationHelpers
+  def sign_in(user)
+    password = 'somecomplicatedpassword'
+    user.update!(password: password)
+    Fabricate(:email_token, confirmed: true, user: user)
+    post "/session.json", { login: user.username, password: password }
+    expect(response).to be_success
+  end
+end