Protocol Buffers (Protobuf), originally developed by Google, is a free and open-source cross-platform data format used to serialize structured data.
It is useful in developing applications that communicate with each other over a network or for storing data.
The method is based on:
An interface description language that describes the data structure (called message), defined in a proto definition file (.proto).
An application (protoc) used for:
generating a stream of bytes starting from the .proto description
parsing a stream of bytes to generate a .proto definition file