To be clear, Grumpy cannot yet run YouTube's Python codebase. There's still a lot of work to do on the standard library.

There are a handful of C extensions for JSON, protobufs, etc that YouTube uses, but mostly they're small utility functions written by us to optimize particularly hot code paths.

Is the plan to use grumpc to transpile the code to Go and then work in Go in the future, or is the plan to keep coding in Python and add a grumpy step before deploying?

(If the former, you could just update the code to use the standard Go JSON/etc packages..)

The idea is to continue to write code in Python. The transpiled code is not suitable for working with directly. That said, there is the possibility of rewriting bits and pieces in Go (e.g. performance critical stuff) and then call into it from Python. Sort of a hybrid approach.

I"m also curious about this

Will these be rewritten in go then?