Python typing got fast enough to feel invisible.

Firefly is a new open source type checker and ID language server from meta,

written in Rust, with a focus on instant feedback and real-world developer experience.

Today, we dig into what it is, why it exists, and how it plays with the rest of the Python typing ecosystem.

We have Abby Mitchell, Danny Yang, and Kyle Into from Firefly here to dive into the project.

This is Talk Python to Me.

Episode 523 recorded September 9th, 2025.

Talk Python to me.

Yeah, we ready to roll.

Upgrading the code.

No fear of getting old.

They sink in the air. New frameworks in sight, geeky rap on deck. Quark crew. It's time to unite. We started in pyramid, cruising old school lanes. Had that stable base. Welcome to Talk Pythonemy, the number one podcast for Python developers and data scientists. This is your host, Michael Kennedy. I'm a PSF fellow who's

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