gRPC with .NET: High-Performance Remote Procedure Calls

var queries = new[] { "laptop", "phone", "tablet" };

foreach (var query in queries) {

await call.RequestStream.WriteAsync(new SearchRequest
{
    Query = query,
    Category = Category.Electronics
});

await Task.Delay(1000); // Simulate user typing```
}

await call.RequestStream.CompleteAsync();
await readTask;

Performance Comparison

Benchmarking gRPC vs REST

Performance test results:

Benchmark code:

[MemoryDiagnoser]
public class GrpcVsRestBenchmark
{
```csharp
private ProductService.ProductServiceClient _grpcClient;
private HttpClient _restClient;

[GlobalSetup]
public void Setup()
{
    var channel = GrpcChannel.ForAddress("https://localhost:5001");
    _grpcClient = new ProductService.ProductServiceClient(channel);
    _restClient = new HttpClient { BaseAddress = new Uri("https://localhost:5002") };
}

[Benchmark]
public async Task<Product> gRPC_GetProduct()
{
    var response = await _grpcClient.GetProductAsync(
        new GetProductRequest { Id = 123 });
    return response.Product;
}

[Benchmark]
public async Task<ProductDto> REST_GetProduct()
{
    return await _restClient.GetFromJsonAsync<ProductDto>("/api/products/123");
}```
}

Authentication

JWT Token Authentication

Server-side interceptor:

public class JwtAuthInterceptor : Interceptor
{
```csharp
private readonly ILogger<JwtAuthInterceptor> _logger;
private readonly ITokenValidator _tokenValidator;

public JwtAuthInterceptor(
    ILogger<JwtAuthInterceptor> logger,
    ITokenValidator tokenValidator)
{
    _logger = logger;
    _tokenValidator = tokenValidator;
}

public override async Task<TResponse> UnaryServerHandler<TRequest, TResponse>(
    TRequest request,
    ServerCallContext context,
    UnaryServerMethod<TRequest, TResponse> continuation)
{
    var authHeader = context.RequestHeaders.GetValue("authorization");
    
    if (string.IsNullOrEmpty(authHeader) || !authHeader.StartsWith("Bearer "))
    {
        throw new RpcException(new Status(
            StatusCode.Unauthenticated,
            "Missing or invalid authorization header"));
    }
    
    var token = authHeader.Substring("Bearer ".Length);
    
    if (!await _tokenValidator.ValidateAsync(token))
    {
        throw new RpcException(new Status(
            StatusCode.Unauthenticated,
            "Invalid token"));
    }
    
    return await continuation(request, context);
}```
}

// Registration
builder.Services.AddGrpc(options =>
{
```text
options.Interceptors.Add<JwtAuthInterceptor>();```


});

Client-side credentials:

var credentials = CallCredentials.FromInterceptor((context, metadata) =>
{
```text
var token = GetAccessToken();
metadata.Add("Authorization", $"Bearer {token}");
return Task.CompletedTask;```
});

var channel = GrpcChannel.ForAddress("https://localhost:5001", new GrpcChannelOptions
{
```text
Credentials = ChannelCredentials.Create(
    new SslCredentials(),
    credentials)```
});

var client = new ProductService.ProductServiceClient(channel);

Error Handling

Status Codes

Common gRPC status codes:

public override async Task<GetProductResponse> GetProduct(
```text
GetProductRequest request,
ServerCallContext context)```
{
```text
if (request.Id <= 0)
{
    throw new RpcException(new Status(
        StatusCode.InvalidArgument,
        "Product ID must be positive"));
}

var product = await _repository.GetByIdAsync(request.Id);

if (product == null)
{
    throw new RpcException(new Status(
        StatusCode.NotFound,
        $"Product {request.Id} not found"));
}

if (!await _authService.CanAccessProduct(context.GetHttpContext().User, product))
{
    throw new RpcException(new Status(
        StatusCode.PermissionDenied,
        "Access denied"));
}

return MapToResponse(product);```
}

Client Error Handling

Retry with Polly:

var retryPolicy = Policy
```javascript
.Handle<RpcException>(ex => 
    ex.StatusCode == StatusCode.Unavailable ||
    ex.StatusCode == StatusCode.DeadlineExceeded)
.WaitAndRetryAsync(3, retryAttempt => 
    TimeSpan.FromSeconds(Math.Pow(2, retryAttempt)));

await retryPolicy.ExecuteAsync(async () => {

var response = await client.GetProductAsync(
    new GetProductRequest { Id = 123 });
return response.Product;```
});

Deadlines and Cancellation

Figure: Configuration and management dashboard with status overview.

Setting deadlines:

// Server: enforce 5-second timeout
var deadline = DateTime.UtcNow.AddSeconds(5);

var response = await client.GetProductAsync(
```text
new GetProductRequest { Id = 123 },
deadline: deadline);

// Client: propagate cancellation token var cts = new CancellationTokenSource(TimeSpan.FromSeconds(10));

try {

var response = await client.GetProductAsync(
    new GetProductRequest { Id = 123 },
    cancellationToken: cts.Token);```
}
catch (RpcException ex) when (ex.StatusCode == StatusCode.DeadlineExceeded)
{
```text
Console.WriteLine("Request timed out");```
}

Best Practices

1. Use HTTP/2: Required for gRPC, enable with Kestrel configuration
2. Enable Compression: Reduce payload sizes further with gzip
3. Implement Health Checks: Use gRPC health checking protocol
4. Set Deadlines: Prevent hanging requests with timeouts
5. Handle Cancellation: Respect CancellationToken in streaming scenarios
6. Version Services: Use package versioning for breaking changes
7. Monitor Performance: Track request latency and payload sizes

Troubleshooting

HTTP/2 Not Enabled:

// appsettings.json
{
  "Kestrel": {
```text
"EndpointDefaults": {
  "Protocols": "Http2"
}```
  }
}

Large Message Errors:

builder.Services.AddGrpc(options =>
{
```text
options.MaxReceiveMessageSize = 16 * 1024 * 1024; // 16 MB
options.MaxSendMessageSize = 16 * 1024 * 1024;```
});

Architecture Decision and Tradeoffs

When designing application development solutions with .NET, consider these key architectural trade-offs:

Recommendation: Start with the managed approach for most workloads and move to custom only when specific requirements demand it.

Validation and Versioning

• Last validated: April 2026
• Validate examples against your tenant, region, and SKU constraints before production rollout.
• Keep module, CLI, and SDK versions pinned in automation pipelines and review quarterly.

Security and Governance Considerations

• Apply least-privilege access using RBAC roles and just-in-time elevation for admin tasks.
• Store secrets in managed secret stores and avoid embedding credentials in scripts or source files.
• Enable audit logging, data protection policies, and periodic access reviews for regulated workloads.

Cost and Performance Notes

• Define budgets and alerts, then monitor usage and cost trends continuously after go-live.
• Baseline performance with synthetic and real-user checks before and after major changes.
• Scale resources with measured thresholds and revisit sizing after usage pattern changes.

Official Microsoft References

• https://learn.microsoft.com/dotnet/
• https://learn.microsoft.com/aspnet/core/
• https://learn.microsoft.com/azure/developer/dotnet/

Public Examples from Official Sources

• These examples are sourced from official public Microsoft documentation and sample repositories.
• Documentation examples: https://learn.microsoft.com/dotnet/
• Sample repositories: https://github.com/dotnet/samples
• Prefer adapting these examples to your tenant, subscriptions, and governance requirements before production use.

Key Takeaways

• gRPC delivers 65% smaller payloads and 2.6x higher throughput vs REST
• Protocol Buffers provide strongly-typed, language-agnostic contracts
• Streaming patterns enable real-time bidirectional communication
• HTTP/2 multiplexing eliminates connection overhead
• Authentication and error handling require gRPC-specific approaches

Next Steps

• Implement gRPC-Web for browser clients
• Add reflection for dynamic tooling like grpcui
• Explore gRPC transcoding to expose REST endpoints
• Use gRPC load balancing with Consul or Kubernetes

Additional Resources

• gRPC in .NET
• Protocol Buffers Language Guide
• gRPC Performance Best Practices

Fast calls, strong types.