diff --git a/.github/workflows/integration.yml b/.github/workflows/integration.yml
index 7b98811..86f74ad 100644
--- a/.github/workflows/integration.yml
+++ b/.github/workflows/integration.yml
@@ -23,6 +23,9 @@ jobs:
       - name: Install Dependencies
         run: yarn install --frozen-lockfile
 
+      - name: TSC
+        run: yarn run tsc
+
       - name: Test
         run: yarn run coverage
 
diff --git a/package.json b/package.json
index 7c3e994..26afdf7 100644
--- a/package.json
+++ b/package.json
@@ -5,6 +5,7 @@
     "build": "vite build",
     "dev": "vite",
     "preview": "vite preview",
+    "tsc": "tsc",
     "test": "vitest",
     "coverage": "vitest run --coverage",
     "lint": "eslint . --ext ts,tsx --report-unused-disable-directives --max-warnings 0"
diff --git a/src/components/message/MessageAttachments.tsx b/src/components/message/MessageAttachments.tsx
index b76ca5a..e8c8e36 100644
--- a/src/components/message/MessageAttachments.tsx
+++ b/src/components/message/MessageAttachments.tsx
@@ -1,8 +1,8 @@
 import { ImageList, ImageListItem } from '@mui/material'
 import { FC, useCallback, useState } from 'react'
 import Lightbox from 'react-image-lightbox'
-import { Message } from '../../api/Message'
 import 'react-image-lightbox/style.css'
+import { Message } from '../../api/Message'
 
 interface Props {
   message: Message
@@ -11,7 +11,7 @@ interface Props {
 const MessageAttachements: FC<Props> = ({ message }) => {
   const [imageLightboxOpen, setImageLightboxOpen] = useState<boolean>(false)
   const [imageIndex, setImageIndex] = useState<number>(0)
-  const attachments = message.attachments
+  const attachments = message.attachments || []
 
   const openImageLightbox = useCallback(() => setImageLightboxOpen(true), [])
   const closeImageLightbox = useCallback(() => setImageLightboxOpen(false), [])
diff --git a/src/components/message/MessageFormCounter.test.tsx b/src/components/message/MessageFormCounter.test.tsx
index 4f25165..b8b6782 100644
--- a/src/components/message/MessageFormCounter.test.tsx
+++ b/src/components/message/MessageFormCounter.test.tsx
@@ -1,4 +1,3 @@
-import React from 'react'
 import { render, screen } from '@testing-library/react'
 import MessageFormCounter from './MessageFormCounter'
 
diff --git a/src/components/ticker/LocationSearch.tsx b/src/components/ticker/LocationSearch.tsx
index 828bd78..a6abeb3 100644
--- a/src/components/ticker/LocationSearch.tsx
+++ b/src/components/ticker/LocationSearch.tsx
@@ -1,5 +1,5 @@
-import React, { FC, useRef, useState } from 'react'
 import { Autocomplete, TextField } from '@mui/material'
+import React, { FC, useRef, useState } from 'react'
 
 interface SearchResult {
   place_id: number
@@ -28,7 +28,7 @@ const LocationSearch: FC<Props> = ({ callback }) => {
   const [options, setOptions] = useState<SearchResult[]>([])
   const previousController = useRef<AbortController>()
 
-  const handleInputChange = (event: React.SyntheticEvent, value: string) => {
+  const handleInputChange = (_: React.SyntheticEvent, value: string) => {
     if (previousController.current) {
       previousController.current.abort()
     }
@@ -44,7 +44,7 @@ const LocationSearch: FC<Props> = ({ callback }) => {
       })
   }
 
-  const handleChange = (event: React.SyntheticEvent, value: SearchResult | null) => {
+  const handleChange = (_: React.SyntheticEvent, value: SearchResult | null) => {
     if (value) {
       callback({ title: value?.display_name, lat: value?.lat, lon: value?.lon })
     }
diff --git a/src/components/ticker/TickerModalForm.tsx b/src/components/ticker/TickerModalForm.tsx
index 8e635c0..02fb3c2 100644
--- a/src/components/ticker/TickerModalForm.tsx
+++ b/src/components/ticker/TickerModalForm.tsx
@@ -1,10 +1,10 @@
 import { Tab, Tabs } from '@mui/material'
 import React, { FC, useState } from 'react'
 import { Ticker } from '../../api/Ticker'
+import Modal from '../common/Modal'
 import TabPanel from '../common/TabPanel'
-import TickerForm from './form/TickerForm'
 import TickerSocialConnections from './TickerSocialConnections'
-import Modal from '../common/Modal'
+import TickerForm from './form/TickerForm'
 
 interface Props {
   onClose: () => void
@@ -15,7 +15,7 @@ interface Props {
 const TickerModalForm: FC<Props> = ({ onClose, open, ticker }) => {
   const [tabValue, setTabValue] = useState<number>(0)
 
-  const handleTabChange = (e: React.SyntheticEvent, value: number) => {
+  const handleTabChange = (_: React.SyntheticEvent, value: number) => {
     setTabValue(value)
   }
 
diff --git a/src/theme/ThemeProvider.tsx b/src/theme/ThemeProvider.tsx
index 77e10a1..b8348d3 100644
--- a/src/theme/ThemeProvider.tsx
+++ b/src/theme/ThemeProvider.tsx
@@ -1,10 +1,10 @@
-import React, { FC, ReactNode } from 'react'
-import { ThemeProvider as MUIThemeProvider, createTheme, StyledEngineProvider, CssBaseline, alpha } from '@mui/material'
+import { CssBaseline, ThemeProvider as MUIThemeProvider, StyledEngineProvider, alpha, createTheme } from '@mui/material'
+import { FC, ReactNode } from 'react'
 import GlobalStyles from './GlobalStyles'
+import customShadows from './customShadows'
 import palette from './palette'
 import shadows from './shadows'
 import typography from './typography'
-import customShadows from './customShadows'
 
 const theme = createTheme({
   palette: palette,
diff --git a/src/views/SettingsView.test.tsx b/src/views/SettingsView.test.tsx
index 29f45ea..5aa8c86 100644
--- a/src/views/SettingsView.test.tsx
+++ b/src/views/SettingsView.test.tsx
@@ -1,11 +1,11 @@
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import { render, screen } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import sign from 'jwt-encode'
 import { MemoryRouter } from 'react-router'
+import { vi } from 'vitest'
 import { AuthProvider } from '../contexts/AuthContext'
-import sign from 'jwt-encode'
 import SettingsView from './SettingsView'
-import userEvent from '@testing-library/user-event'
-import { vi } from 'vitest'
 
 describe('SettingsView', function () {
   const jwt = sign({ id: 1, email: 'louis@systemli.org', roles: ['admin', 'user'] }, 'secret')
@@ -38,7 +38,7 @@ describe('SettingsView', function () {
 
   beforeEach(() => {
     vi.spyOn(window.localStorage.__proto__, 'getItem').mockReturnValue(jwt)
-    fetch.resetMocks()
+    fetchMock.resetMocks()
   })
 
   function setup() {
@@ -61,7 +61,7 @@ describe('SettingsView', function () {
   }
 
   test('renders settings and open dialogs', async function () {
-    fetch.mockIf(/^http:\/\/localhost:8080\/.*$/, (request: Request) => {
+    fetchMock.mockIf(/^http:\/\/localhost:8080\/.*$/, (request: Request) => {
       if (request.url.endsWith('/admin/settings/inactive_settings')) {
         return Promise.resolve(inactiveSettingsResponse)
       }
@@ -114,7 +114,7 @@ describe('SettingsView', function () {
   })
 
   test('settings could not fetched', async function () {
-    fetch.mockReject(new Error('network error'))
+    fetchMock.mockReject(new Error('network error'))
     setup()
 
     const loaders = screen.getAllByText(/loading/i)
diff --git a/src/views/TickerView.tsx b/src/views/TickerView.tsx
index 21ae7f6..89ff6d7 100644
--- a/src/views/TickerView.tsx
+++ b/src/views/TickerView.tsx
@@ -26,7 +26,7 @@ const TickerView: FC = () => {
     )
   }
 
-  const ticker = data?.data.ticker
+  const ticker = data?.data?.ticker
 
   return (
     <Layout>
diff --git a/src/views/UsersView.test.tsx b/src/views/UsersView.test.tsx
index 8a9d12f..926a032 100644
--- a/src/views/UsersView.test.tsx
+++ b/src/views/UsersView.test.tsx
@@ -1,18 +1,18 @@
 import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
 import { render, screen } from '@testing-library/react'
+import userEvent from '@testing-library/user-event'
+import sign from 'jwt-encode'
 import { MemoryRouter } from 'react-router'
+import { vi } from 'vitest'
 import { AuthProvider } from '../contexts/AuthContext'
 import UsersView from './UsersView'
-import sign from 'jwt-encode'
-import userEvent from '@testing-library/user-event'
-import { vi } from 'vitest'
 
 describe('UsersView', function () {
   const jwt = sign({ id: 1, email: 'louis@systemli.org', roles: ['admin', 'user'] }, 'secret')
 
   beforeEach(() => {
     vi.spyOn(window.localStorage.__proto__, 'getItem').mockReturnValue(jwt)
-    fetch.resetMocks()
+    fetchMock.resetMocks()
   })
 
   function setup() {
@@ -35,7 +35,7 @@ describe('UsersView', function () {
   }
 
   test('renders list', async function () {
-    fetch.mockResponseOnce(
+    fetchMock.mockResponseOnce(
       JSON.stringify({
         data: {
           users: [
@@ -57,7 +57,7 @@ describe('UsersView', function () {
 
   test('open new users dialog', async function () {
     setup()
-    fetch.mockIf(
+    fetchMock.mockIf(
       /\/v1\/admin\/users/i,
       JSON.stringify({
         data: {
@@ -65,7 +65,7 @@ describe('UsersView', function () {
         },
       })
     )
-    fetch.mockIf(
+    fetchMock.mockIf(
       /\/v1\/admin\/tickers/i,
       JSON.stringify({
         data: {
@@ -91,7 +91,7 @@ describe('UsersView', function () {
   })
 
   test('open dialog for existing user', async function () {
-    fetch.mockIf(
+    fetchMock.mockIf(
       /\/v1\/admin\/users/i,
       JSON.stringify({
         data: {
@@ -154,7 +154,7 @@ describe('UsersView', function () {
   })
 
   test('user list could not fetched', async function () {
-    fetch.mockReject(new Error('network error'))
+    fetchMock.mockReject(new Error('network error'))
     setup()
 
     expect(screen.getByText(/loading/i)).toBeInTheDocument()