gRPC vs HTTP

Feature	gRPC	HTTP APIs with JSON
Contract	Required (.proto)	Optional (OpenAPI)
Protocol	HTTP/2	HTTP
Payload	Protobuf (small, binary)	JSON (large, human readable)
Prescriptiveness	Strict specification	Loose. Any HTTP is valid.
Streaming	Client, server, bi-directional	Client, server
Browser support	No (requires grpc-web)	Yes
Security	Transport (TLS)	Transport (TLS)
Client code-generation	Yes	OpenAPI + third-party tooling