Things don't always go as intended in real-world applications. Data may be erroneous, services may not be available, or requests may fail. Because of this, error management is crucial when developing gRPC services in.NET. This post will explain how error handling functions in gRPC, how it differs from REST, and how to correctly implement it in ASP.NET Core using straightforward examples.

How gRPC Handles Errors
gRPC employs its own error model, in contrast to REST APIs, which often return errors as HTTP status codes (such as 404 or 500).

Within gRPC:

  • Status codes are used to indicate errors.
  • Every error has a message and a status code.
  • RpcException is used to send errors.

Error handling becomes more organized and uniform across services as a result.

gRPC Status Codes
Some commonly used gRPC status codes are:

  • OK: Request was successful
  • InvalidArgument: The input data is wrong
  • NotFound: Resource not found
  • Unauthenticated: User is not logged in
  • PermissionDenied: User does not have access
  • Internal: Server error

These codes help the client understand what went wrong.

Throwing Errors in gRPC Service
In .NET, you handle errors by throwing an RpcException.
public override Task<MyResponse> GetData(MyRequest request, ServerCallContext context)
{
    if (string.IsNullOrEmpty(request.Name))
    {
        throw new RpcException(new Status(StatusCode.InvalidArgument, "Name is required"));
    }

    return Task.FromResult(new MyResponse
    {
        Message = "Success"
    });
}

Here:

  • We check if the input is valid
  • If not, we throw an error with a proper status code

Handling Errors on Client Side
The client should also handle errors properly.
try
{
    var response = await client.GetDataAsync(new MyRequest());
}
catch (RpcException ex)
{
    Console.WriteLine($"Error: {ex.Status.Detail}");
    Console.WriteLine($"Code: {ex.StatusCode}");
}

This allows the client to:

  • Read the error message
  • Take action based on the error type

Using Interceptors for Global Error Handling
Instead of handling errors in every method, you can use interceptors.
public class ExceptionInterceptor : Interceptor
{
    public override async Task<TResponse> UnaryServerHandler<TRequest, TResponse>(
        TRequest request,
        ServerCallContext context,
        UnaryServerMethod<TRequest, TResponse> continuation)
    {
        try
        {
            return await continuation(request, context);
        }
        catch (Exception ex)
        {
            throw new RpcException(new Status(StatusCode.Internal, "Something went wrong"));
        }
    }
}

Register it:
builder.Services.AddGrpc(options =>
{
    options.Interceptors.Add<ExceptionInterceptor>();
});

This helps you manage errors in one central place.

Best Practices for Error Handling

  • Always return meaningful error messages
  • Use correct status codes
  • Avoid exposing sensitive information
  • Use interceptors for global handling
  • Log errors for debugging

These practices make your application more reliable and easier to maintain.

Common Mistakes to Avoid

  • Returning generic errors without details
  • Using wrong status codes
  • Not handling exceptions on client side
  • Exposing internal server details

Avoiding these mistakes improves your API quality.

When Proper Error Handling Matters
Error handling is especially important in:

  • Microservices
  • Distributed systems
  • APIs used by multiple clients

Without proper error handling, debugging becomes very difficult.

Summary

RpcException and structured status codes are the foundation of gRPC.NET error handling. It offers a consistent, tightly typed method for client and server error communication, in contrast to REST. You may create reliable and production-ready gRPC services by employing appropriate status codes, managing exceptions appropriately, and implementing global error handling through interceptors.

HostForLIFE ASP.NET Core 10.0 Hosting

European Best, cheap and reliable ASP.NET Core 10.0 hosting with instant activation. HostForLIFE.eu is #1 Recommended Windows and ASP.NET hosting in European Continent. With 99.99% Uptime Guaranteed of Relibility, Stability and Performace. HostForLIFE.eu security team is constantly monitoring the entire network for unusual behaviour. We deliver hosting solution including Shared hosting, Cloud hosting, Reseller hosting, Dedicated Servers, and IT as Service for companies of all size.