What's new in ASP.NET Core in .NET 9

This article highlights the most significant changes in ASP.NET Core in .NET 9 with links to relevant documentation.

Static asset delivery optimization

MapStaticAssets routing endpoint conventions is a new feature that optimizes the delivery of static assets in ASP.NET Core apps.

For information on static asset delivery for Blazor apps, see xref:blazor/fundamentals/static-files?view=aspnetcore-9.0.

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Blazor

This section describes new features for Blazor.

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SignalR

This section describes new features for SignalR.

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Minimal APIs

This section describes new features for Minimal APIs.

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OpenAPI

This section describes new features for OpenAPI

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Authentication and authorization

This section describes new features for authentication and authorization.

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Miscellaneous

The following sections describe miscellaneous new features.

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Breaking changes

Use the articles in Breaking changes in .NET to find breaking changes that might apply when upgrading an app to a newer version of .NET.