Login with Passkeys in a .NET MAUI App | Community Feed

.NET MAUI Preview 7 quietly added a real cross-platform Passkeys API — not a browser wrapper, but a bridge to the native passkey APIs on each platform. Tony Edwards explores what a production implementation actually looks like, from the client call to the security-sensitive server work.

What you’ll learn

The MAUI surface — Passkeys.IsSupported, CreateAsync, and AssertAsync, and why the JSON-in/JSON-out design keeps challenges and verification on the server
Registration and authentication flows — the full begin/finish round trips between app, native authenticator, and an ASP.NET Core Identity backend
Server setup — relying-party ID, ValidateOrigin for native app origins, and Identity schema version 3 for storing passkeys
Token-based sign-in — using PerformPasskeyAssertionAsync to verify without a cookie session and issue your normal access/refresh tokens
Platform association — Apple Associated Domains, Android Digital Asset Links, ceremony state, PreferImmediatelyAvailable, and handling cancellation cleanly

Read the full ~21 minute walkthrough for the endpoint code, the gotchas, and links to the MAUI sample and backend.