6 articles

Decorating the default ResourceOwnerPasswordValidator to allow users to authenticate with email or phone number in addition to username, using a custom Mongo-based UserStore.

Replacing IAuthenticationSchemeProvider in WebApplicationFactory to inject a fake user for integration tests — no JWT tokens or identity server required.

Composing ASP.NET Identity manually to get UserManager and SignInManager without the RoleManager — starting from AddIdentityCore and adding the missing pieces.

Inside ASP.NET Identity's default token provider setup — TokenOptions class, AddDefaultTokenProviders internals, manual per-provider registration, and per-provider UserManager API.

Exploring the EFCore UserStore ReplaceClaimAsync — why it matches claims by both type and value, the IdentityUserClaim schema without Issuer, and a cleaner refactoring proposal.

Tracing SignInManager.SignInAsync through every layer — SignInWithClaimsAsync, HttpContext extension, IAuthenticationService, scheme handler dispatch, and CookieAuthenticationHandler.