REST to gRPC Migration Checklist
A migration checklist for moving internal communication from REST to gRPC. It covers proto schema conventions, gateways, interceptor auth, deadlines, and side-by-side rollout.
When to Use This Checklist
Use this checklist to migrate internal service-to-service communication from REST to gRPC, a high-performance RPC framework built on HTTP/2 and Protocol Buffers. gRPC offers strong typing, efficient binary serialization, and streaming, which makes it a good fit for internal, high-throughput calls. It is usually a poor fit for browser-facing public APIs, so plan a gateway for those consumers.
How to Use This Checklist
Start by selecting internal, high-traffic endpoints that benefit most. Define Protocol Buffer schemas and adopt strict field-numbering conventions, because reusing or renumbering fields silently corrupts wire compatibility. Decide where streaming RPCs add value. Provide a gRPC gateway or dual stack for clients that still need REST. Map auth to interceptors, configure deadlines and retries, and propagate trace context through gRPC metadata.
Run both protocols side by side and migrate consumers incrementally with REST kept available for rollback.
What Good Looks Like
A clean migration has well-structured proto schemas with stable field numbers, generated clients verified by contract tests, and interceptor-based auth. Deadlines, retries, and load balancing are configured, trace context flows through metadata, and a gateway serves clients that need REST. gRPC and REST run side by side until consumers have migrated and the REST path can be retired.
Common Pitfalls
The most dangerous error is reusing Protocol Buffer field numbers, which breaks compatibility invisibly. Teams expose gRPC directly to browsers without a gateway and hit support gaps. Missing deadlines let slow calls pile up. Cutting over without a side-by-side period removes the ability to fall back to REST.
Related Resources
See gRPC best practices, api-backward-compatibility for safe proto evolution, contract-driven development with Pact for verification, and distributed tracing best practices for metadata propagation. The circuit breaker pattern protects gRPC dependencies.