Unlock Faster Browser‑to‑Server Calls: .NET gRPC‑Web Now Officially Released

In January Microsoft announced experimental support for gRPC‑Web for .NET, and it has now been officially released.

gRPC is Google’s open‑source high‑performance RPC framework that supports many languages, including .NET. It is designed for mobile and HTTP/2, but browsers cannot directly use the gRPC HTTP/2 protocol because they lack fine‑grained request control. gRPC‑Web provides a standardized protocol that makes gRPC usable in browsers.

gRPC‑Web (gRPC for Web Clients) is a JavaScript library that lets web applications communicate directly with backend gRPC services without an HTTP proxy. It expands gRPC usage to scenarios such as:

Calling ASP.NET Core gRPC applications from browsers, including JavaScript SPAs and .NET Blazor WebAssembly apps

Hosting ASP.NET Core gRPC services on IIS and Azure App Service

Calling gRPC from non‑.NET Core platforms; since HttpClient on all .NET platforms lacks HTTP/2 support, gRPC‑Web can be used from Blazor and Xamarin to call gRPC services

Microsoft is working with the Blazor team to improve the end‑to‑end developer experience of using gRPC‑Web in Blazor WebAssembly apps.

According to Microsoft, gRPC offers clear performance advantages over JSON. In the default Blazor template, using gRPC halves the data transferred on a data‑fetch page, reducing payload size from 627 bytes to 309 bytes.

The .NET gRPC‑Web packages are now available on NuGet:

Grpc.AspNetCore.Web – adds gRPC‑Web support to ASP.NET Core gRPC services

Grpc.Net.Client.Web – enables .NET clients to call gRPC‑Web endpoints

For more details, see the official documentation or try the sample applications.