One-liner: REST uses JSON over HTTP/1. 1 and is human-readable; gRPC uses binary Protocol Buffers over HTTP/2 and is 5-10× faster — pick based on who's calling your service. 📡 REST — Representational State Transfer The universal language of the web.
Source: [Dev.to](https://dev.to/gouranga-das-khulna/service-to-service-communication-grpc-vs-rest-1c5d)