aspnetcore/release-notes/aspnetcore-10/includes/sse.md
ASP.NET Core now supports returning a ServerSentEvents result using the TypedResults.ServerSentEvents API. This feature is supported in both Minimal APIs and controller-based apps.
Server-Sent Events is a server push technology that allows a server to send a stream of event messages to a client over a single HTTP connection. In .NET the event messages are represented as SseItem<T> objects, which may contain an event type, an ID, and a data payload of type T.
The TypedResults class has a new static method called ServerSentEvents that can be used to return a ServerSentEvents result. The first parameter to this method is an IAsyncEnumerable<SseItem<T>> that represents the stream of event messages to be sent to the client.
The following example illustrates how to use the TypedResults.ServerSentEvents API to return a stream of heart rate events as JSON objects to the client:
:::code language="csharp" source="~/fundamentals/minimal-apis/10.0-samples/MinimalServerSentEvents/Program.cs" id="snippet_json" :::
For more information, see:
TypedResults.ServerSentEvents API to return a stream of heart rate events as string, ServerSentEvents, and JSON objects to the client.TypedResults.ServerSentEvents API to return a stream of heart rate events as string, ServerSentEvents, and JSON objects to the client.