The degree you "need" to support the full schema format depends entirely on the language you're using. In Go you only need the annotated structures, or in Java

The degree you "need" to support the full schema format depends entirely on the language you're using. In Go you only need the annotated structures, or in Java you only need a mapping between field number and name, and the languages' own reflection capabilities can handle the rest. Yes, strings, bytes, and substructures all appear in the same in the wire format. Just like strings, bytes, and dates all appear the same in JSON. If you're trying to write a generic protobuf viewer like wodenokoto suggests, you can make reasonable assumptions about the contents 99% of the time based on the data, and show the user multiple options if you're not sure. There are already lots of tools that do this, but none very well integrated into mainstream development workflows.