Building for the agentic web with .NET 11

TL;DR

• 1

  .NET 11 is built around six priorities: Daniel Roth frames the release around feedback, platform fundamentals, the modern stack, distributed apps with Aspire, agentic web apps, and better AI-assisted development.

• 2

  Many of the biggest wins come "just by upgrading": Kestrel gets lower TLS handshake overhead, malformed request handling, Zstandard compression, stronger CSRF protection via fetch metadata headers, and native OpenTelemetry semantic convention tags without extra ASP.NET Core instrumentation.

• 3

  Blazor is getting serious SSR parity with MVC: New pieces like environment boundary, temp data, labels, display name, output caching, session-state binding, non-interactive client-side validation, localized validation messages, and async validation close gaps that have bothered Blazor developers for a while.

• 4

  WebAssembly gets a practical near-term boost while CoreCLR migration is underway: .NET 11 previews the shift from Mono to CoreCLR for Blazor WebAssembly, and ships a new Blazor web worker template today so CPU-heavy jobs can run off the UI thread, even if it is more like a separate process than true multithreading.

• 5

  Aspire integration now gives Blazor WebAssembly a real production hosting story: The new Blazor gateway hosts static assets, proxies API calls so you can skip CORS, flows service discovery config to the browser, collects OpenTelemetry, supports session affinity, and replaces the old dev server with something deployable.

• 6

  Microsoft is trying to make .NET a first-class stack for agents and coding agents alike: Roth shows Agent Framework plus AGUI endpoints in ASP.NET Core, prototype Blazor AI components for streaming and human-in-the-loop flows, and .NET Skills plugins that helped an AI turn a 300-400 line monolithic Kanban board into cleaner subcomponents.