https://medium.com/@kevin.snyder.codes/protobufs-the-good-the-bad-and-the-ugly-e2478308031e

Protobufs are one of the “new hotness” coming out of Google. By defining a basic schema, you can generate strongly typed models for a multitude of programming languages. These models can be used by your code bases to handle data transfer, serialization, validation, and all other sorts of data goodness.

Protobufs are sent over the wire in a binary format. This format is not self-describing — there are no keys or other descriptive information sent with the data. To properly understand the data being sent, you need the original protobuf it was created with. However, the benefits of this format are twofold: message are extremely small, and are backwards- and forwards-compatible as long as you’re smart about your protobuf schema design.