gRPCurl

grpcurl is a command-line tool that lets you interact with gRPC servers. It's

basically curl for gRPC servers.

The main purpose for this tool is to invoke RPC methods on a gRPC server from

the command-line. gRPC servers use a binary encoding on the wire (protocol

buffers, or "protobufs" for short). So they are basically impossible to interact

with using regular curl (and older versions of curl that do not support HTTP/2

are of course non-starters). This program accepts messages using JSON encoding,

which is much more friendly for both humans and scripts.

With this tool you can also browse the schema for gRPC services, either by

querying a server that supports server reflection, by reading proto source

files, or by loading in compiled "protoset" files (files that contain encoded

file descriptor protos). In fact, the way the tool transforms JSON request data

into a binary encoded protobuf is using that very same schema. So, if the server

you interact with does not support reflection, you will either need the proto

source files that define the service or need protoset files that grpcurl can

use.