Avro is one of the most mature and experienced serialization systems for binary. As with gRPC, Avro also has a communication layer using RPC.

Avro uses a .avsc file, which is defined in JSON format, for the serialization process. The file may be composed of both types that provide JSON, or more complex types from Avro itself.

Even being very mature as a tool, Avro is the poorest in terms of native compatibility with other programming languages other than Java, Ruby, C++, C#, and Python. As the project is open source, there is a whole range of drivers that provide compatibility with Avro that come from the community.