ASP.NET Core

Replace the Stream.Read or Write call with ReadAsync/WriteAsync. As a last resort, set AllowSynchronousIO on Kestrel, IIS, or per-request via IHttpBodyControlFeature.

ASP.NET Core's scope validation throws this when a singleton would capture a scoped dependency for the rest of the process. Make the consumer scoped, or take IServiceScopeFactory and create a scope on demand.

ASP.NET Core throws this when a constructor asks for a type that was never registered, was registered on the wrong container, or was added after the host was built. Three concrete fixes cover almost every case.

If GetConnectionString returns null in .NET 11, your appsettings.json is missing the key, not copied to the build output, or the wrong environment file is being selected. Three checks fix 95% of cases.

A complete guide to wiring Serilog 4.x and Seq 2025.2 into a .NET 11 ASP.NET Core app: AddSerilog vs UseSerilog, two-stage bootstrap logging, JSON configuration, enrichers, request logging, OpenTelemetry trace correlation, API keys, and the production gotchas around buffering, retention, and signal level.

Wire OpenTelemetry traces, metrics, and logs into a .NET 11 ASP.NET Core app with the OTLP exporter, then ship them to a free, self-hosted backend: the standalone Aspire Dashboard for local dev, Jaeger and SigNoz for self-hosted production, and the OpenTelemetry Collector when you need both.

A complete guide to per-endpoint rate limiting in ASP.NET Core 11: when to pick fixed window vs sliding window vs token bucket vs concurrency, how RequireRateLimiting and [EnableRateLimiting] differ, partitioning by user or IP, the OnRejected handler, and the distributed deployment pitfall everyone hits.

Stream Claude responses from an ASP.NET Core 11 minimal API end-to-end: the official Anthropic .NET SDK, TypedResults.ServerSentEvents, SseItem, IAsyncEnumerable, cancellation flow, and the gotchas that buffer your tokens silently. With Claude Sonnet 4.6 and Opus 4.7 examples.

Asp.Versioning 10.0 is the first release that targets .NET 10 and the new Microsoft.AspNetCore.OpenApi pipeline. Sander ten Brinke's April 23 walkthrough shows how to register one OpenAPI document per API version with WithDocumentPerVersion().

In .NET 11 the OpenAPI document is generated by Microsoft.AspNetCore.OpenApi and Swagger UI is no longer in the template. Here is how to wire Bearer, OAuth2 with PKCE, and OpenID Connect so the Authorize button actually works.