marimo ships a JetBrains plugin for its reactive Python notebooks

Sources: marimo blog, HN 49004464
Summary: marimo announced a PyCharm and JetBrains IDE plugin on 2026-07-21, distributed through the JetBrains Marketplace with the plugin source on GitHub. marimo notebooks are stored as plain .py files and re-run dependent cells automatically, so they diff and merge under git. The plugin runs notebooks next to project code inside the IDE, exposes the module reloader so library edits feed straight back into a running notebook, switches between the interactive notebook view and the source view, runs notebooks in sandbox mode with isolated dependencies when uv is present, and manages the local server port and process lifecycle.
Why it matters: The plain-.py notebook format plus in-IDE execution removes the usual reason notebook work lives outside the repository and outside code review.