diff --git a/client/sagas/index.js b/client/sagas/index.js
index ec4074af58..13e755f9fa 100644
--- a/client/sagas/index.js
+++ b/client/sagas/index.js
@@ -8,6 +8,7 @@ import codeStorageSaga from './code-storage-saga';
 import gitterSaga from './gitter-saga';
 import mouseTrapSaga from './mouse-trap-saga';
 import analyticsSaga from './analytics-saga';
+import nightModeSaga from './night-mode-saga';
 
 export default [
   errSaga,
@@ -19,5 +20,6 @@ export default [
   codeStorageSaga,
   gitterSaga,
   mouseTrapSaga,
-  analyticsSaga
+  analyticsSaga,
+  nightModeSaga
 ];
diff --git a/client/sagas/night-mode-saga.js b/client/sagas/night-mode-saga.js
new file mode 100644
index 0000000000..efc5e9d5c9
--- /dev/null
+++ b/client/sagas/night-mode-saga.js
@@ -0,0 +1,47 @@
+import { Observable } from 'rx';
+import { postJSON$ } from '../../common/utils/ajax-stream';
+import types from '../../common/app/redux/types';
+import {
+  addThemeToBody,
+  updateTheme,
+  createErrorObservable
+} from '../../common/app/redux/actions';
+
+export default function nightModeSaga(
+  actions,
+  getState,
+  { document: { body } }
+) {
+  const toggleBodyClass = actions
+    .filter(({ type }) => types.addThemeToBody === type)
+    .doOnNext(({ payload: theme }) => {
+      if (theme === 'night') {
+        body.classList.add('night');
+      } else {
+        body.classList.remove('night');
+      }
+    })
+    .filter(() => false);
+  const toggle = actions
+    .filter(({ type }) => types.toggleNightMode === type);
+
+  const optimistic = toggle
+    .flatMap(() => {
+      const { app: { theme } } = getState();
+      const newTheme = !theme || theme === 'default' ? 'night' : 'default';
+      return Observable.of(
+        updateTheme(newTheme),
+        addThemeToBody(newTheme)
+      );
+    });
+
+  const ajax = toggle
+    .debounce(250)
+    .flatMapLatest(() => {
+      const { app: { theme, csrfToken: _csrf } } = getState();
+      return postJSON$('/update-my-theme', { _csrf, theme })
+        .catch(createErrorObservable);
+    });
+
+  return Observable.merge(optimistic, toggleBodyClass, ajax);
+}
diff --git a/common/app/redux/actions.js b/common/app/redux/actions.js
index 71d6c50e02..83fefaf255 100644
--- a/common/app/redux/actions.js
+++ b/common/app/redux/actions.js
@@ -188,4 +188,13 @@ export const closeHelpChat = createAction(
   })
 );
 
-export const toggleNightMode = createAction(types.toggleNightMode);
+export const toggleNightMode = createAction(
+  types.toggleNightMode,
+  // we use this function to avoid hanging onto the eventObject
+  // so that react can recycle it
+  () => null
+);
+// updateTheme(theme: /night|default/) => Action
+export const updateTheme = createAction(types.updateTheme);
+// addThemeToBody(theme: /night|default/) => Action
+export const addThemeToBody = createAction(types.addThemeToBody);
diff --git a/common/app/redux/fetch-user-saga.js b/common/app/redux/fetch-user-saga.js
index ba2f6cbc4e..5afa9b5872 100644
--- a/common/app/redux/fetch-user-saga.js
+++ b/common/app/redux/fetch-user-saga.js
@@ -5,11 +5,12 @@ import {
   updateThisUser,
   updateCompletedChallenges,
   createErrorObservable,
-  showSignIn
+  showSignIn,
+  updateTheme,
+  addThemeToBody
 } from './actions';
 
 const { fetchUser } = types;
-
 export default function getUserSaga(action$, getState, { services }) {
   return action$
     .filter(action => action.type === fetchUser)
@@ -19,10 +20,14 @@ export default function getUserSaga(action$, getState, { services }) {
           if (!entities || !result) {
             return Observable.just(showSignIn());
           }
+          const user = entities.user[result];
+          const isNightMode = user.theme === 'night';
           return Observable.of(
             addUser(entities),
+            updateCompletedChallenges(result),
             updateThisUser(result),
-            updateCompletedChallenges(result)
+            isNightMode ? updateTheme(user.theme) : null,
+            isNightMode ? addThemeToBody(user.theme) : null
           );
         })
         .catch(createErrorObservable);
diff --git a/common/app/redux/reducer.js b/common/app/redux/reducer.js
index b73b20cccf..4ccf742824 100644
--- a/common/app/redux/reducer.js
+++ b/common/app/redux/reducer.js
@@ -10,7 +10,8 @@ const initialState = {
   windowHeight: 0,
   navHeight: 0,
   isMainChatOpen: false,
-  isHelpChatOpen: false
+  isHelpChatOpen: false,
+  theme: 'default'
 };
 
 export default handleActions(
@@ -29,6 +30,10 @@ export default handleActions(
       ...state,
       lang: payload
     }),
+    [types.updateTheme]: (state, { payload = 'default' }) => ({
+      ...state,
+      theme: payload
+    }),
     [types.showSignIn]: state => ({
       ...state,
       shouldShowSignIn: true
diff --git a/common/app/redux/types.js b/common/app/redux/types.js
index d0ec7220cb..1da89d89c3 100644
--- a/common/app/redux/types.js
+++ b/common/app/redux/types.js
@@ -18,7 +18,6 @@ export default createTypes([
   'updateMyCurrentChallenge',
 
   'handleError',
-  'toggleNightMode',
   // used to hit the server
   'hardGoTo',
   'delayedRedirect',
@@ -44,5 +43,10 @@ export default createTypes([
 
   'openHelpChat',
   'closeHelpChat',
-  'toggleHelpChat'
+  'toggleHelpChat',
+
+  // night mode
+  'toggleNightMode',
+  'updateTheme',
+  'addThemeToBody'
 ], 'app');
diff --git a/common/models/user.js b/common/models/user.js
index ee3bfb5285..3134479076 100644
--- a/common/models/user.js
+++ b/common/models/user.js
@@ -599,6 +599,7 @@ module.exports = function(User) {
       .toPromise();
   };
 
+  // deprecated. remove once live
   User.remoteMethod(
     'updateTheme',
     {
diff --git a/server/boot/settings.js b/server/boot/settings.js
index 496a2df249..9cc0900407 100644
--- a/server/boot/settings.js
+++ b/server/boot/settings.js
@@ -64,8 +64,26 @@ export default function settingsController(app) {
     );
   }
 
+  function updateMyTheme(req, res, next) {
+    req.checkBody('theme', 'Theme is invalid.').isLength({ min: 4 });
+    const { body: { theme } } = req;
+    const errors = req.validationErrors(true);
+    if (errors) {
+      return res.status(403).json({ errors });
+    }
+    if (req.user.theme === theme) {
+      return res.json({ msg: 'Theme already set' });
+    }
+    return req.user.updateTheme('' + theme)
+      .then(
+        data => res.json(data),
+        next
+      );
+  }
+
   api.post(
     '/toggle-lockdown',
+    ifNoUser401,
     toggleUserFlag('isLocked')
   );
   api.post(
@@ -99,5 +117,12 @@ export default function settingsController(app) {
     ifNoUser401,
     updateMyCurrentChallenge
   );
+
+  api.post(
+    '/update-my-theme',
+    ifNoUser401,
+    updateMyTheme
+  );
+
   app.use(api);
 }