# Step 4: Connect to an API

Real-world applications do not live in isolation — they need APIs to talk to. Setup your app to talk to an API.

**Let's change our application to fetch the data from the API.**

```typescript jsx
const App = () => {
  const [todos, setTodos] = useState<Todo[]>([]);

  useEffect(() => {
    fetch('/api/todos')
      .then(_ => _.json())
      .then(setTodos);
  }, []);

  function addTodo() {
    fetch('/api/addTodo', {
      method: 'POST',
      body: ''
    })
      .then(_ => _.json())
      .then(newTodo => {
        setTodos([...todos, newTodo]);
      });
  }

  return (
    <>
      <h1>Todos</h1>
      <ul>
        {todos.map(t => (
          <li className={'todo'}>{t.title}</li>
        ))}
      </ul>
      <button id={'add-todo'} onClick={addTodo}>
        Add Todo
      </button>
    </>
  );
};

export default App
```

!!!!!
Run "nx serve todos" and open http://localhost:4200. What do you see?
!!!!!
"the server responded with a status of 404 (Not Found)" in Console.
Blank screen.
Exception rendered on the screen.