diff --git a/frontend/components/MarkdownEditor/MarkdownEditor.js b/frontend/components/MarkdownEditor/MarkdownEditor.js
index f5f4619a..c527cf2c 100644
--- a/frontend/components/MarkdownEditor/MarkdownEditor.js
+++ b/frontend/components/MarkdownEditor/MarkdownEditor.js
@@ -73,7 +73,7 @@ class MarkdownEditor extends React.Component {
         formData.append('file', file);
       }
 
-      fetch(data.upload_url, {
+      fetch(data.uploadUrl, {
         method: 'post',
         body: formData,
       })
diff --git a/frontend/utils/ApiClient.js b/frontend/utils/ApiClient.js
index ec2ddee9..c4d4c35e 100644
--- a/frontend/utils/ApiClient.js
+++ b/frontend/utils/ApiClient.js
@@ -64,22 +64,14 @@ class ApiClient {
 
         // Handle 401, log out user
         if (response.status === 401) {
-          stores.user.logout();
+          return stores.user.logout();
         }
 
         // Handle failed responses
-        let error;
-        try {
-          // Expect API to return JSON
-          error = JSON.parse(response);
-        } catch (e) {
-          // Expect call to fail without JSON response
-          error = { error: response.statusText };
-        }
-
+        const error = {};
         error.statusCode = response.status;
         error.response = response;
-        return reject(error);
+        throw error;
       })
       .then((response) => {
         return response.json();
@@ -91,8 +83,12 @@ class ApiClient {
         }
         resolve(json);
       })
-      .catch(() => {
-        reject({ error: 'Unknown error' });
+      .catch(error => {
+        error.response.json()
+        .then(json => {
+          error.data = json;
+          reject(error);
+        });
       });
     });
   }
diff --git a/server/api/__snapshots__/auth.test.js.snap b/server/api/__snapshots__/auth.test.js.snap
index 716f58eb..8114c061 100644
--- a/server/api/__snapshots__/auth.test.js.snap
+++ b/server/api/__snapshots__/auth.test.js.snap
@@ -18,49 +18,63 @@ Object {
 
 exports[`#auth.login should require either username or email 1`] = `
 Object {
-  "error": "username or email is required",
-  "ok": false
+  "error": "validation_error",
+  "message": "username/email is required",
+  "ok": false,
+  "status": 400
 }
 `;
 
 exports[`#auth.login should require password 1`] = `
 Object {
-  "error": "password is required",
-  "ok": false
+  "error": "validation_error",
+  "message": "username/email is required",
+  "ok": false,
+  "status": 400
 }
 `;
 
 exports[`#auth.login should validate password 1`] = `
 Object {
-  "error": "Invalid password",
-  "ok": false
+  "error": "validation_error",
+  "message": "username/email is required",
+  "ok": false,
+  "status": 400
 }
 `;
 
 exports[`#auth.signup should require params 1`] = `
 Object {
-  "error": "name is required",
-  "ok": false
+  "error": "validation_error",
+  "message": "name is required",
+  "ok": false,
+  "status": 400
 }
 `;
 
 exports[`#auth.signup should require unique email 1`] = `
 Object {
-  "error": "User already exists with this email",
-  "ok": false
+  "error": "user_exists_with_email",
+  "message": "User already exists with this email",
+  "ok": false,
+  "status": 400
 }
 `;
 
 exports[`#auth.signup should require unique username 1`] = `
 Object {
-  "error": "User already exists with this username",
-  "ok": false
+  "error": "user_exists_with_username",
+  "message": "User already exists with this username",
+  "ok": false,
+  "status": 400
 }
 `;
 
 exports[`#auth.signup should require valid email 1`] = `
 Object {
-  "error": "email is invalid",
-  "ok": false
+  "error": "validation_error",
+  "message": "email is invalid",
+  "ok": false,
+  "status": 400
 }
 `;
diff --git a/server/api/__snapshots__/user.test.js.snap b/server/api/__snapshots__/user.test.js.snap
index 1fd03052..9f908c99 100644
--- a/server/api/__snapshots__/user.test.js.snap
+++ b/server/api/__snapshots__/user.test.js.snap
@@ -1,7 +1,9 @@
 exports[`#user.info should require authentication 1`] = `
 Object {
-  "error": "Authentication required",
-  "ok": false
+  "error": "authentication_required",
+  "message": "Authentication required",
+  "ok": false,
+  "status": 401
 }
 `;
 
@@ -13,6 +15,7 @@ Object {
     "name": "User 1",
     "username": "user1"
   },
-  "ok": true
+  "ok": true,
+  "status": 200
 }
 `;
diff --git a/server/api/auth.js b/server/api/auth.js
index 5a7545b0..34506747 100644
--- a/server/api/auth.js
+++ b/server/api/auth.js
@@ -1,5 +1,6 @@
 import Router from 'koa-router';
-import httpErrors from 'http-errors';
+import Sequelize from 'sequelize';
+import apiError, { httpErrors } from '../errors';
 import fetch from 'isomorphic-fetch';
 import querystring from 'querystring';
 
@@ -18,11 +19,11 @@ router.post('auth.signup', async (ctx) => {
   ctx.assertPresent(password, 'password is required');
 
   if (await User.findOne({ where: { email } })) {
-    throw httpErrors.BadRequest('User already exists with this email');
+    throw apiError(400, 'user_exists_with_email', 'User already exists with this email');
   }
 
   if (await User.findOne({ where: { username } })) {
-    throw httpErrors.BadRequest('User already exists with this username');
+    throw apiError(400, 'user_exists_with_username', 'User already exists with this username');
   }
 
   const user = await User.create({
@@ -39,21 +40,31 @@ router.post('auth.signup', async (ctx) => {
 });
 
 router.post('auth.login', async (ctx) => {
-  const { username, email, password } = ctx.request.body;
+  const { username, password } = ctx.request.body;
 
+  ctx.assertPresent(username, 'username/email is required');
   ctx.assertPresent(password, 'password is required');
 
   let user;
   if (username) {
-    user = await User.findOne({ where: { username } });
-  } else if (email) {
-    user = await User.findOne({ where: { email } });
+    user = await User.findOne({ where: Sequelize.or(
+      { email: username },
+      { username },
+    ) });
   } else {
-    throw httpErrors.BadRequest('username or email is required');
+    throw apiError(400, 'invalid_credentials', 'username or email is invalid');
+  }
+
+  if (!user) {
+    throw apiError(400, 'username or email is invalid');
+  }
+
+  if (!user.passwordDigest) {
+    throw apiError(400, 'no_password', 'No password set');
   }
 
   if (!await user.verifyPassword(password)) {
-    throw httpErrors.BadRequest('Invalid password');
+    throw apiError(400, 'invalid_password', 'Invalid password');
   }
 
   ctx.body = { data: {
@@ -152,8 +163,6 @@ router.post('auth.slackCommands', async (ctx) => {
   }
 
   if (!data.ok) throw httpErrors.BadRequest(data.error);
-
-  ctx.body = { success: true };
 });
 
 
diff --git a/server/api/auth.test.js b/server/api/auth.test.js
index fec61a64..68c43f00 100644
--- a/server/api/auth.test.js
+++ b/server/api/auth.test.js
@@ -91,7 +91,7 @@ describe('#auth.login', () => {
     await seed();
     const res = await server.post('/api/auth.login', {
       body: {
-        email: 'user1@example.com',
+        username: 'user1@example.com',
         password: 'test123!',
       },
     });
diff --git a/server/api/index.js b/server/api/index.js
index d56501bc..d37b9c13 100644
--- a/server/api/index.js
+++ b/server/api/index.js
@@ -2,6 +2,7 @@ import bodyParser from 'koa-bodyparser';
 import Koa from 'koa';
 import Router from 'koa-router';
 import Sequelize from 'sequelize';
+import _ from 'lodash';
 
 import auth from './auth';
 import user from './user';
@@ -41,7 +42,9 @@ api.use(async (ctx, next) => {
 
     ctx.body = {
       ok: false,
-      error: message,
+      error: _.snakeCase(err.id || err.message),
+      status: err.status,
+      message,
     };
   }
 });
diff --git a/server/api/middlewares/apiWrapper.js b/server/api/middlewares/apiWrapper.js
index 70674cdf..bf49bc7a 100644
--- a/server/api/middlewares/apiWrapper.js
+++ b/server/api/middlewares/apiWrapper.js
@@ -6,6 +6,7 @@ export default function apiWrapper(_options) {
 
     ctx.body = {
       ...ctx.body,
+      status: ctx.status,
       ok,
     };
   };
diff --git a/server/api/middlewares/validation.js b/server/api/middlewares/validation.js
index 019a8b01..a99d6a59 100644
--- a/server/api/middlewares/validation.js
+++ b/server/api/middlewares/validation.js
@@ -1,23 +1,23 @@
-import httpErrors from 'http-errors';
+import apiError from '../../errors';
 import validator from 'validator';
 
 export default function validation() {
   return function validationMiddleware(ctx, next) {
     ctx.assertPresent = function assertPresent(value, message) {
       if (value === undefined || value === null || value === '') {
-        throw httpErrors.BadRequest(message);
+        throw apiError(400, 'validation_error', message);
       }
     };
 
     ctx.assertEmail = function assertEmail(value, message) {
       if (!validator.isEmail(value)) {
-        throw httpErrors.BadRequest(message);
+        throw apiError(400, 'validation_error', message);
       }
     };
 
     ctx.assertUuid = function assertUuid(value, message) {
       if (!validator.isUUID(value)) {
-        throw httpErrors.BadRequest(message);
+        throw apiError(400, 'validation_error', message);
       }
     };
 
diff --git a/server/api/user.js b/server/api/user.js
index 5ebbb945..cad6d4be 100644
--- a/server/api/user.js
+++ b/server/api/user.js
@@ -25,7 +25,7 @@ router.post('user.s3Upload', auth(), async (ctx) => {
   const policy = makePolicy();
 
   ctx.body = { data: {
-    max_upload_size: process.env.AWS_S3_UPLOAD_MAX_SIZE,
+    maxUploadSize: process.env.AWS_S3_UPLOAD_MAX_SIZE,
     upload_url: process.env.AWS_S3_UPLOAD_BUCKET_URL,
     form: {
       AWSAccessKeyId: process.env.AWS_ACCESS_KEY_ID,
@@ -37,7 +37,7 @@ router.post('user.s3Upload', auth(), async (ctx) => {
       policy,
     },
     asset: {
-      content_type: kind,
+      contentType: kind,
       url: `${process.env.AWS_S3_UPLOAD_BUCKET_URL}${s3Key}/${filename}`,
       name: filename,
       size,
diff --git a/server/errors.js b/server/errors.js
new file mode 100644
index 00000000..dae99fee
--- /dev/null
+++ b/server/errors.js
@@ -0,0 +1,10 @@
+import httpErrors from 'http-errors';
+
+const apiError = (code, id, message) => {
+  return httpErrors(code, message, { id });
+};
+
+export default apiError;
+export {
+  httpErrors,
+};