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: 06/08/2024
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 5.

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## Blazor

This section describes new features for Blazor.

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

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

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

## SignalR

This section describes new features for SignalR.

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

## Minimal APIs

This section describes new features for minimal APIs.

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

## OpenAPI

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

## Authentication and authorization

This section describes new features for authentication and authorization.

[!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)]