Observable updates

I’m pretty late noticing Observable Notebooks 2.0 Technology Preview (looks like it was announced 2025-07-29), but delighted to see that Observable continues to experiment. The tent-poles of this preview seem to be:

• A defined, simple file format for notebooks that’s basically HTML with a restricted set of tags; plus some tooling for working with such notebooks
• Replacing the “Observable JavaScript” runtime with a just-plain-JavaScript runtime
• A new macOS desktop app designed for authoring the notebooks

All of these look like positive steps forward; I love that they’re willing to re-think and simplify the core reactive runtime specifically to make it more interoperable with plain files and standard tooling. The notebook format calls out Python as an allowed cell type; presumably one could round-trip Jupyter notebooks through this format.

I’m less certain about the desktop app — I watched their demo, but haven’t tried the app myself, so don’t take me too seriously. But, it looks like the main feature is nice AI integration so that you author the notebook primarily by asking the AI to write cells for you, and this seems very similar to marimo’s browser-based editor. I guess maybe some UI affordances can be marginally nicer in a native app, but this seems like a big stretch.