diff --git a/app/index.js b/app/index.js
index f90af9838..25f0bd6ac 100644
--- a/app/index.js
+++ b/app/index.js
@@ -25,8 +25,6 @@ import Members from 'scenes/Settings/Members';
 import Slack from 'scenes/Settings/Slack';
 import Shares from 'scenes/Settings/Shares';
 import Tokens from 'scenes/Settings/Tokens';
-import SlackAuth from 'scenes/SlackAuth';
-import ErrorAuth from 'scenes/ErrorAuth';
 import Error404 from 'scenes/Error404';
 
 import ErrorBoundary from 'components/ErrorBoundary';
@@ -61,14 +59,6 @@ if (element) {
             <ScrollToTop>
               <Switch>
                 <Route exact path="/" component={Home} />
-                <Route exact path="/auth/slack" component={SlackAuth} />
-                <Route
-                  exact
-                  path="/auth/slack/commands"
-                  component={SlackAuth}
-                />
-                <Route exact path="/auth/slack/post" component={SlackAuth} />
-                <Route exact path="/auth/error" component={ErrorAuth} />
                 <Route exact path="/share/:shareId" component={Document} />
                 <Auth>
                   <Layout>
diff --git a/app/scenes/ErrorAuth/ErrorAuth.js b/app/scenes/ErrorAuth/ErrorAuth.js
deleted file mode 100644
index 97e19f2e5..000000000
--- a/app/scenes/ErrorAuth/ErrorAuth.js
+++ /dev/null
@@ -1,23 +0,0 @@
-// @flow
-import * as React from 'react';
-import { Link } from 'react-router-dom';
-
-import CenteredContent from 'components/CenteredContent';
-import PageTitle from 'components/PageTitle';
-
-class ErrorAuth extends React.Component<*> {
-  render() {
-    return (
-      <CenteredContent>
-        <PageTitle title="Authentication error" />
-        <h1>Authentication failed</h1>
-
-        <p>
-          We were unable to log you in. <Link to="/">Please try again.</Link>
-        </p>
-      </CenteredContent>
-    );
-  }
-}
-
-export default ErrorAuth;
diff --git a/app/scenes/ErrorAuth/index.js b/app/scenes/ErrorAuth/index.js
deleted file mode 100644
index 0e961642b..000000000
--- a/app/scenes/ErrorAuth/index.js
+++ /dev/null
@@ -1,3 +0,0 @@
-// @flow
-import ErrorAuth from './ErrorAuth';
-export default ErrorAuth;
diff --git a/server/auth/slack.js b/server/auth/slack.js
index eb3eb58fc..ac1eb89fa 100644
--- a/server/auth/slack.js
+++ b/server/auth/slack.js
@@ -1,97 +1,86 @@
 // @flow
 import Router from 'koa-router';
+import addHours from 'date-fns/add_hours';
+import addMonths from 'date-fns/add_months';
 import auth from '../middlewares/authentication';
 import { slackAuth } from '../../shared/utils/routeHelpers';
-import { presentUser, presentTeam } from '../presenters';
 import { Authentication, Integration, User, Team } from '../models';
 import * as Slack from '../slack';
 
 const router = new Router();
 
-router.get('auth.slack', async ctx => {
+// start the oauth process and redirect user to Slack
+router.get('slack', async ctx => {
   const state = Math.random()
     .toString(36)
     .substring(7);
 
   ctx.cookies.set('state', state, {
     httpOnly: false,
-    expires: new Date('2100'),
+    expires: addHours(new Date(), 1),
   });
   ctx.redirect(slackAuth(state));
 });
 
-router.post('auth.slack', async ctx => {
-  const { code } = ctx.body;
-  ctx.assertPresent(code, 'code is required');
+// signin callback from Slack
+router.get('slack.callback', async ctx => {
+  const { code, error, state } = ctx.request.query;
+  ctx.assertPresent(code || error, 'code is required');
+  ctx.assertPresent(state, 'state is required');
+
+  if (state !== ctx.cookies.get('state') || error) {
+    ctx.redirect('/?notice=auth-error');
+    return;
+  }
 
   const data = await Slack.oauthAccess(code);
 
-  let user = await User.findOne({
-    where: { service: 'slack', serviceId: data.user.id },
-  });
-  let team = await Team.findOne({ where: { slackId: data.team.id } });
-  const isFirstUser = !team;
-
-  if (team) {
-    team.name = data.team.name;
-    team.slackData = data.team;
-    await team.save();
-  } else {
-    team = await Team.create({
-      name: data.team.name,
+  const [team, isFirstUser] = await Team.findOrCreate({
+    where: {
       slackId: data.team.id,
-      slackData: data.team,
-    });
-  }
+    },
+    defaults: {
+      name: data.team.name,
+      avatarUrl: data.team.image_88,
+    },
+  });
 
-  if (user) {
-    user.slackAccessToken = data.access_token;
-    user.slackData = data.user;
-    await user.save();
-  } else {
-    user = await User.create({
+  const [user] = await User.findOrCreate({
+    where: {
       service: 'slack',
       serviceId: data.user.id,
+      teamId: team.id,
+    },
+    defaults: {
       name: data.user.name,
       email: data.user.email,
-      teamId: team.id,
       isAdmin: isFirstUser,
-      slackData: data.user,
-      slackAccessToken: data.access_token,
-    });
-
-    // Set initial avatar
-    await user.updateAvatar();
-    await user.save();
-  }
+      avatarUrl: data.user.image_192,
+    },
+  });
 
   if (isFirstUser) {
     await team.createFirstCollection(user.id);
   }
 
-  // Signal to backend that the user is logged in.
-  // This is only used to signal SSR rendering, not
-  // used for auth.
-  ctx.cookies.set('loggedIn', 'true', {
+  ctx.cookies.set('lastSignedIn', 'slack', {
     httpOnly: false,
     expires: new Date('2100'),
   });
+  ctx.cookies.set('accessToken', user.getJwtToken(), {
+    httpOnly: false,
+    expires: addMonths(new Date(), 1),
+  });
 
-  ctx.body = {
-    data: {
-      user: await presentUser(ctx, user),
-      team: await presentTeam(ctx, team),
-      accessToken: user.getJwtToken(),
-    },
-  };
+  ctx.redirect('/');
 });
 
-router.post('auth.slackCommands', auth(), async ctx => {
+router.post('slack.commands', auth(), async ctx => {
   const { code } = ctx.body;
   ctx.assertPresent(code, 'code is required');
 
   const user = ctx.state.user;
-  const endpoint = `${process.env.URL || ''}/auth/slack/commands`;
+  const endpoint = `${process.env.URL || ''}/auth/slack.commands`;
   const data = await Slack.oauthAccess(code, endpoint);
   const serviceId = 'slack';
 
@@ -112,12 +101,12 @@ router.post('auth.slackCommands', auth(), async ctx => {
   });
 });
 
-router.post('auth.slackPost', auth(), async ctx => {
+router.post('slack.post', auth(), async ctx => {
   const { code, collectionId } = ctx.body;
   ctx.assertPresent(code, 'code is required');
 
   const user = ctx.state.user;
-  const endpoint = `${process.env.URL || ''}/auth/slack/post`;
+  const endpoint = `${process.env.URL || ''}/auth/slack.post`;
   const data = await Slack.oauthAccess(code, endpoint);
   const serviceId = 'slack';
 
diff --git a/server/pages/Home.js b/server/pages/Home.js
index 43ff10962..43511c561 100644
--- a/server/pages/Home.js
+++ b/server/pages/Home.js
@@ -10,7 +10,7 @@ import { developers, githubUrl } from '../../shared/utils/routeHelpers';
 import { color } from '../../shared/styles/constants';
 
 type Props = {
-  notice?: 'google-hd',
+  notice?: 'google-hd' | 'auth-error',
   lastSignedIn: string,
   googleSigninEnabled: boolean,
   slackSigninEnabled: boolean,
@@ -38,6 +38,12 @@ function Home(props: Props) {
               try signing in with your company Google account.
             </Notice>
           )}
+          {props.notice === 'auth-error' && (
+            <Notice>
+              Authentication failed - we were unable to sign you in at this
+              time. Please try again.
+            </Notice>
+          )}
         </Hero>
         <Features reverse={{ mobile: true, tablet: false, desktop: false }}>
           <Grid.Unit size={{ desktop: 1 / 3, tablet: 1 / 2 }}>
diff --git a/server/slack.js b/server/slack.js
index 2d06d26aa..d33ebf485 100644
--- a/server/slack.js
+++ b/server/slack.js
@@ -44,7 +44,7 @@ export async function request(endpoint: string, body: Object) {
 
 export async function oauthAccess(
   code: string,
-  redirect_uri: string = `${process.env.URL || ''}/auth/slack`
+  redirect_uri: string = `${process.env.URL || ''}/auth/slack.callback`
 ) {
   return request('oauth.access', {
     client_id: process.env.SLACK_KEY,
diff --git a/shared/utils/routeHelpers.js b/shared/utils/routeHelpers.js
index a9c7772a9..ff05000de 100644
--- a/shared/utils/routeHelpers.js
+++ b/shared/utils/routeHelpers.js
@@ -8,7 +8,7 @@ export function slackAuth(
     'identity.avatar',
     'identity.team',
   ],
-  redirectUri: string = `${process.env.URL}/auth/slack`
+  redirectUri: string = `${process.env.URL}/auth/slack.callback`
 ): string {
   const baseUrl = 'https://slack.com/oauth/authorize';
   const params = {