We switched our very large Django monolith codebase over to ty — the trick for us was generating stubs for Django models and having tooling keep those stubs in sync with the actual models.

Went from type checking taking ~10 minutes in CI to now taking ~15 seconds and runs on pre-commit.

Absolute game changer, I think we spent $10k in claude credits and did the entire mypy -> ty refactor in about 3 weeks.