> For AI agents: the complete documentation index is available at /llms.txt, the full documentation bundle is available at /llms-full.txt.

# App.tsx

The entry identifier when using [Self-controlled Routing](/guides/concept/entries.md#self-controlled-routing) in the application.

`App.tsx` is not the actual application entry; Modern.js will automatically generate the real entry file, which is roughly as follows:

```js
// runtime-global-context
import { setGlobalContext } from '@modern-js/runtime/context';
import App from '@_modern_js_src/App';

setGlobalContext({
  App,
});

// index.tsx
import './runtime-global-context';
import { createRoot } from '@modern-js/runtime/react';
import { render } from '@modern-js/runtime/browser';

const ModernRoot = createRoot();

render(<ModernRoot />, 'root');
```

When `createRoot` is executed, it will retrieve the registered Global App and generate the actual React component.

:::note
In scenarios with multiple entry points, each entry can have its own independent `App.tsx`. For more details, see [Entry Points](/guides/concept/entries.md).
:::