What are the disadvantages of gRPC?

gRPC has notable limitations: (1) Browser support — gRPC requires HTTP/2 with trailers, which browsers don't natively support for XHR/Fetch; gRPC-Web (with a proxy) is required for browser clients, adding infrastructure complexity; (2) Not human-readable — Protobuf binary messages can't be inspected with curl or browser DevTools; debugging requires tools like grpcurl, Postman, or Bloomrpc; (3) Learning curve — Proto IDL, code generation, and gRPC concepts require upfront learning; REST with JSON is more approachable; (4) Ecosystem maturity — REST tooling (API gateways, monitoring, testing) is more mature and widely supported; (5) No standard caching — HTTP GET-based REST caches naturally via CDN/proxies; gRPC POST-based requests don't cache easily; (6) Protobuf schema management — maintaining .proto files, breaking change prevention, and schema registry requires discipline and tooling; (7) Limited support in some languages — gRPC support quality varies across language ecosystems.