"Protocol Buffers" is a binary serialization format and technology, released to the open source community by Google in 2008.

There are various implementations of Protocol Buffers in .NET. This project is a fairly close port of the Google Java implementation.

There are two main parts:

ProtoGen.exe, which takes binary representations of protocol buffer descriptors (as generated by the "stock" protoc binary supplied by Google) and creates C# source code. This is only required at build time.

Google.ProtocolBuffers.dll, which is a supporting library. This is required at execution time.

As of April 2011, all development for this project will be performed in the Google Code Mercurial repository; the old GitHub project is obsolete.

There is API documentation available here, which can also be downloaded as a CHM file.