This guide describes how to use the protocol buffer language to structure your protocol buffer data, including .proto file syntax and how to generate data access classes from your .proto files. It covers the proto2 version of the protocol buffers language: for information on the newer proto3 syntax, see the Proto3 Language Guide.

This is a reference guide – for a step by step example that uses many of the features described in this document, see the tutorial for your chosen language.