What is Protocol Buffer?

Protocol buffers (Protobuf) are Google’s language-neutral, platform-neutral, extensible mechanism for serializing structured data – think XML, but smaller, faster, and simpler. (Source: protobuf.dev)

Protocol Buffers supported programming languages:

Language
C++ (include C++ runtime and protoc)
Java
Python
Objective-C
C#
Ruby
Go
PHP
Dart
JavaScript

For, detail implementation each language, you can check on this link