rpc_dart

rpc_dart is a transport-agnostic RPC framework for Dart. Write your service contracts once and run them over any transport — in-process, HTTP/2, WebSocket, or Dart Isolates — without changing the service code. It uses gRPC-compatible 5-byte message framing and supports all four RPC call patterns.

pub.dev DeepWiki Context7

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RPC Patterns

Pattern	Signature
Unary	Future<Response> method(Request)
Server streaming	Stream<Response> method(Request)
Client streaming	Future<Response> method(Stream<Request>)
Bidirectional streaming	Stream<Response> method(Stream<Request>)

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Packages

Package	Description
rpc_dart	Core framework: contracts, endpoints, transports interface, context
rpc_dart_generator	build_runner code generator — turns annotated interfaces into ready-to-use responders and callers
rpc_dart_compression	Cross-platform gzip codec (works on web/wasm)
rpc_dart_opentelemetry	OpenTelemetry interceptor with W3C Trace Context propagation
rpc_dart_http2	HTTP/2 transport (native)
rpc_dart_http	HTTP/1.1 transport (cross-platform, web/wasm)
rpc_dart_websocket	WebSocket transport (cross-platform)
rpc_dart_isolate	Dart Isolate transport (IO + web workers)

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Installation

dependencies:
  rpc_dart: ^2.6.1

dev_dependencies:
  rpc_dart_generator: ^0.1.6
  build_runner: any

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Minimal Example

The shortest path to a working RPC call — unary, in-process, zero-copy (no serialization):

import 'package:rpc_dart/rpc_dart.dart';

// Shared types
class AddRequest  { final int a, b; AddRequest(this.a, this.b); }
class AddResponse { final int result; AddResponse(this.result); }

// Server contract
final class CalculatorResponder extends RpcResponderContract {
  CalculatorResponder() : super('Calculator');

  @override
  void setup() {
    addUnaryMethod<AddRequest, AddResponse>(
      methodName: 'add',
      handler: (req, {context}) async => AddResponse(req.a + req.b),
    );
  }
}

void main() async {
  final (callerTransport, responderTransport) = RpcInMemoryTransport.pair();

  final server = RpcResponderEndpoint(transport: responderTransport);
  server.registerServiceContract(CalculatorResponder());
  server.start();

  final callerEndpoint = RpcCallerEndpoint(transport: callerTransport);

  final response = await callerEndpoint.unaryRequest<AddRequest, AddResponse>(
    serviceName: 'Calculator',
    methodName: 'add',
    request: AddRequest(2, 3),
  );

  print(response.result); // 5
}

For real projects use the code generator to avoid writing boilerplate. See the Getting Started guide for a full walkthrough.