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Connect RPC

Connect Resource Provisioning Controller (RPC) is an open-source framework and set of libraries for building networked APIs with Protocol Buffers (API framework / RPC).

  • Supports building RPC APIs using Protocol Buffers with client and server libraries in multiple languages (API framework / RPC).
  • Implements a unified RPC model that works over HTTP/1.1 and HTTP/2 with support for unary and streaming calls (network transport / RPC).
  • Provides first-class compatibility with gRPC and gRPC-Web for interoperability with existing ecosystems (interoperability / RPC).
  • Offers code generation tooling and plugins to produce strongly typed clients and servers from proto definitions (developer tooling / code generation).
  • Supports JSON and binary Protobuf encodings for the same service definitions to address browser and server workloads (data serialization / Application Programming Interface (API) interoperability).

More About Connect Rpc

Connect RPC is an open-source RPC framework that uses Protocol Buffers (Protobuf) (API framework / RPC) to define services and data contracts, and exposes them over HTTP-based transports to support browser, mobile, and server applications. The project focuses on making RPC services accessible through common Hypertext Transfer Protocol (HTTP) infrastructure while maintaining compatibility with existing gRPC (RPC protocol) and gRPC-Web implementations.

The framework provides libraries that allow developers to implement servers and clients that speak a common RPC protocol over HTTP/1.1 and HTTP/2 (network transport / RPC). It supports unary and streaming methods, enabling request-response calls as well as bidirectional or server-side streaming patterns. Connect RPC defines clear mapping between Protobuf service definitions and HTTP endpoints, including standard request and response envelopes, error semantics, and metadata handling, which streamlines integration with load balancers, proxies, and observability systems (API gateway / observability integration).

Connect RPC emphasizes interoperability (interoperability / RPC) by offering compatibility with gRPC and gRPC-Web, allowing services implemented with Connect to interact with existing gRPC clients and servers. It supports both binary Protobuf and JSON encodings (data serialization), making it feasible to serve browser-based applications that require JSON while reusing the same Protobuf schemas used for backend communication. This approach enables multi-platform API strategies where a single service definition can support different client stacks.

The project includes code generation tooling (developer tooling / code generation) that reads Protobuf files and generates strongly typed client and server stubs in supported languages. This reduces boilerplate and provides compile-time safety around request and response shapes, streaming behavior, and error types. The generated code follows conventions for HTTP configuration and transport behavior, which helps standardize how services are exposed and consumed across teams.

In enterprise environments, Connect RPC can be used to build internal and external APIs that run over standard HTTP infrastructure (enterprise integration / API platform). Its design aligns with existing observability, authentication, and routing components that expect HTTP traffic, which can simplify deployment compared to non-HTTP-native RPC protocols. Organizations can use Connect RPC as a unifying layer for Protobuf-based services, supporting both browser clients through gRPC-Web-compatible endpoints and backend services through gRPC-compatible transports while maintaining a single service definition per API.

From a directory and taxonomy perspective, Connect RPC fits in the categories of RPC framework, Protobuf-based API tooling, and HTTP/2 and HTTP/1.1 transport for remote procedure calls. It is relevant for platform engineering teams, API platform owners, and backend service developers who require typed contracts, streaming capabilities, and interoperable RPC semantics over standard web transports.