gRPC is a framework that lets one software service call another over the network as if it were calling a function in its own code. It was built by Google for speed: instead of human-readable text, it sends compact binary messages and keeps connections open to avoid setup costs. That makes it a popular choice for traffic between internal services.
Think of two departments in a company that talk over a dedicated phone line instead of mailing letters. The line is always connected and they speak a tight, agreed shorthand, so each exchange is quick. A REST API is more like sending a clearly written letter in JSON: easy for a human to read, but heavier to send and slower to process at high volume.
The agreed shorthand comes from a file called a protocol buffer, where both sides define the exact shape of every message in advance. From that one definition, gRPC can generate matching code in many languages, so a service written in Go and one written in Java agree on the format automatically. It also supports streaming, where data flows continuously in either direction rather than one request and one reply.
gRPC really pays off inside a system built from microservices, where dozens of small services chat constantly and every millisecond counts. Browsers cannot call it directly, so teams often keep a public API in REST or GraphQL and use gRPC behind the scenes. The downside is that the binary format is harder to inspect by eye when something goes wrong.
At TopDevs we reach for gRPC inside a client’s backend when services need to talk fast and often, while keeping the public-facing layer in a format anything can read.
