OAuth2 provider callback URL schemes

This page covers which redirect URI schemes and hosts Coder accepts, for both admin-created and self-registered applications.

Custom URI schemes (myapp://, vscode://, jetbrains://, etc.) are fully supported for native and desktop applications. The OS routes the redirect back to the registered application without requiring a running HTTP server. A private-use scheme must name a path or an authority, as in com.example.app:/callback or com.example.app://auth/callback. The bare form com.example.app:callback is rejected.

The out-of-band URN urn:ietf:wg:oauth:2.0:oob is accepted from either client type, for clients that display the authorization code for the user to copy rather than receiving it on a redirect. No other URN is accepted.

The following schemes are blocked for security reasons: javascript:, data:, file:, ftp:.

Public clients (token_endpoint_auth_method: none) additionally cannot register mailto:, tel:, or sms: redirect URIs, since those schemes hand off to another app rather than returning an authorization code to the client. Confidential clients are not subject to this restriction.

A cleartext http:// redirect URI is accepted only for a local host. A confidential client may use localhost, 127.0.0.1, [::1], or a .localhost subdomain such as http://app.localhost/callback. A public client is limited to localhost, 127.0.0.1, and [::1]. Every other host must use https://, so that an authorization code is never delivered in the clear. The management API and Dynamic Client Registration apply the same rule, so an administrator cannot store a target that a client could not register for itself.

Coder ignores the port of an http:// redirect URI to localhost, 127.0.0.1, or [::1], for public and confidential clients alike. RFC 8252 requires this for 127.0.0.1 and [::1] so that native apps can choose a port at runtime. Coder applies it to localhost too. A .localhost subdomain still requires an exact port match. Register http://127.0.0.1/callback and present whichever port the client is listening on.

These rules apply to every entry in redirect_uris, not only the first one.

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• Check Troubleshooting for "Invalid Callback URL" and related errors