> ## Documentation Index
> Fetch the complete documentation index at: https://getoverlay.io/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Sign-in and hosted server

> How Overlay Desktop authenticates against Overlay Server.

Official builds authenticate against the hosted Overlay Server at
`https://getoverlay.io`.

Flow:

1. Desktop opens the system browser to the server sign-in page.
2. After success, the browser returns via an `overlay://` callback.
3. Main process validates the handoff and stores session material using OS
   secure storage / Keychain-backed APIs.

Hosted mode still requires Overlay Server for account features, hosted models,
entitlements, and billing. Local notes and some tools can work on-device after
sign-in depending on configuration.