gRPC vs REST
gRPC delivers fast binary RPC with streaming and strict contracts, ideal for internal microservices, while REST offers universal reach, HTTP caching, and easy debugging for public APIs. Many systems use gRPC internally and REST at the edge.
Overview
gRPC and REST both let services talk over HTTP, but with different philosophies. gRPC is a contract-first remote procedure call framework that serializes messages as Protocol Buffers and runs over HTTP/2. REST is an architectural style that models resources as URLs and typically exchanges JSON over HTTP.
Key Differences
Performance is gRPC's headline advantage. Protocol Buffers produce small binary payloads that serialize and parse faster than JSON, and HTTP/2 multiplexes many calls over one connection. For chatty internal traffic this reduces latency and CPU cost noticeably.
Streaming is built into gRPC: a single method can stream from client to server, server to client, or both ways. REST has no native streaming; teams reach for Server-Sent Events or WebSockets to fill the gap.
Contracts differ in rigor. gRPC requires a .proto schema and generates strongly typed client and server stubs across many languages, which keeps services in sync and reduces glue code. REST contracts via OpenAPI are valuable but optional and not enforced by the protocol.
Reach favors REST. Browsers cannot speak raw gRPC, so browser apps need gRPC-Web plus a proxy such as Envoy. REST is callable from any browser, curl, or HTTP client, and benefits from standard HTTP caching, CDNs, and proxies. Debugging binary gRPC also needs specialized tooling like grpcurl and server reflection, whereas REST traffic is human-readable.
When to Choose gRPC
Choose gRPC for internal, east-west communication between microservices where latency, throughput, and strict contracts matter. It is excellent for polyglot environments because generated stubs eliminate hand-written clients, and for use cases that need real-time streaming such as telemetry, chat backends, or live feeds.
When to Choose REST
Choose REST for public APIs, browser-facing endpoints, and integrations where readability, broad tooling, and HTTP caching are important. It is the safer default when consumers are external or unknown, and when developer onboarding speed outweighs raw performance.
Verdict
gRPC wins on performance, streaming, and contract enforcement for internal services; REST wins on reach, caching, and tooling for public and browser-facing APIs. A common pattern is gRPC between backend services and REST (or a thin REST/GraphQL gateway) at the edge for external clients.