How do I add Atlas to my app?

On the frontend, the entire integration is a provider plus a component. In React:

import { AtlasProvider, SignIn, useUser } from '@atlas/react';

function App() {
  const { user, isLoaded } = useUser();
  if (!isLoaded) return <Spinner />;
  if (!user) return <SignIn />;
  return <Dashboard user={user} />;
}

<AtlasProvider publishableKey="pk_live_…">
  <App />
</AtlasProvider>

That gives you sign-in, sign-up, sessions and the current user with no token plumbing of your own. On the backend, verify the session token your frontend sends with your secret key and you get the authenticated user, organization and permissions.

The same model is available for Next.js, Vue, Nuxt, Angular, Svelte, React Native and vanilla JS. See the framework guides at https://developers.atlasauth.net.