Support across languages etc is much less mature but I find thrift serialization format to be much nicer than protobuf. The codegen somehow manages to produce types that look like types I would actually write compared to the monstrosities that protoc generates.

Something like MessagePack or CBOR, and if you want versioning, just have a version field at the start. You don't require a schema to pack/unpack, which I personally think is a good thing.

> You don't require a schema to pack/unpack

Then it hardly solves the same problem Protobuf solves.

Arrow is also becoming a good contender, with the extra benefit it is better optimized for data batches.

CBOR is probably the best and most standards compliant thing out there that I’m aware of.

It’s the new default in a lot of IOT specs, it’s the backbone for deep space communication networks etc..

Maintains interoperability with JSON. Is very much battle tested in very challenging environments.

There are none, protobufs are great.

Depends. ASN.1 is a beast and another industry standard, but unfortunately the best tooling is closed source.

There was ZERO PB tooling in 2000. Just write it for ASN.1 instead.

Mentioned above: https://github.com/stepchowfun/typical