AspNetCore.Docs/aspnetcore/release-notes/aspnetcore-9.0.md

---
title: What's new in ASP.NET Core 9.0
author: rick-anderson
description: Learn about the new features in ASP.NET Core 9.0.
ms.author: riande
ms.custom: mvc
ms.date: 08/10/2024
uid: aspnetcore-9
---
# What's new in ASP.NET Core 9.0

This article highlights the most significant changes in ASP.NET Core 9.0 with links to relevant documentation.

This article has been updated for .NET 9 Preview 7.

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## Blazor

This section describes new features for Blazor.

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/blazor.md)]

## SignalR

This section describes new features for SignalR.

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/signalr.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/signalrActivities.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/signalr-trimming-aot.md)]

## Minimal APIs

This section describes new features for minimal APIs.

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/status500.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/produces-problem.md)]

## OpenAPI

This section describes new features for OpenAPI

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/openApi.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/openAPI_completion.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/transformer-registration.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/openapi-aot.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/prob_validation.md)]

## Authentication and authorization

This section describes new features for authentication and authorization.

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/par.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/oidccustomparms.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/httpsysextendedauth.md)]

## Miscellaneous

The following sections describe miscellaneous new features.

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/hybrid-cache.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/endpoint-metadata.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/debugger.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/fix-for-503s.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/web_asset_delivery.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/asp0026.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/improved-kestrel-connection-metrics.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/customize-named-pipes.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/exception-type-sets-http-status.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/opt_out_metrics.md)]

[!INCLUDE[](~/release-notes/aspnetcore-9/includes/delete_keys.md)]