[kentonv]

They are both zero-copy, but the designs have a number of differences. I compared them back in 2014: https://capnproto.org/news/2014-06-17-capnproto-flatbuffers-...

Disclaimers:

1) I'm the author of Cap'n Proto; I'm probably biased.

2) A lot could have changed since 2014. (Though, obviously, serialization formats need to be backwards-compatible which limits the amount they can change...)

[presscast]

Cool, thanks for this! I'm happily using Cap'n Proto in a side project, and so far have really enjoyed working with it. It's a really impressive piece of engineering.