We launched marimo [1], an open-source reactive Python notebook, last year on HackerNews. Today, the most popular recent feature request in Google Colab’s issue tracker asks for marimo support in Colab [2].

Rather than try to convince Google to replace their notebook with marimo, we decided to just build our own cloud-hosted notebook service instead. We're calling this molab (mo for marimo), and we're launching it today.

You can try it at https://molab.marimo.io

Some features:

- Persistent storage

- Link sharing (notebooks are public but undiscoverable, like secret GitHub Gists)

- Download notebooks to your machine, reuse them as Python scripts or apps

- Upload local notebooks to the cloud from our CLI (coming soon)

- Real-time collaboration (coming soon)

- Configure computational resources to obtain more CPU or GPU (coming soon)

marimo is a modern notebook for modern data workflows; we also built molab on a modern tech stack:

- Notebook dependencies are managed by uv, enabling lighting-fast package installation (thanks to uv’s cache and more generally its performant implementation). uv makes it easy to run molab notebooks locally, too: uvx marimo edit <notebook-url> brings the notebook down to your machine.

- Persistent storage is powered by R2, Cloudflare’s zero-egress object store.

- We use Pydantic logfire to monitor our deployment.

- While our implementation is agnostic to the compute backend (stay tuned!), we’re currently running on Modal for fast startups (not to mention a slick developer experience). Modal sandboxes make it easy for us define containers at runtime, containing notebook code and their dependencies. (Shout out to Eric Zhang from Modal for helping us get started.)

molab is free to use, as long as usage is reasonable. Our goal is to make is as easy as possible for our community to use marimo notebooks.

Finally, learn more at our announcement blog: https://marimo.io/blog/announcing-molab

If this interests you, please give molab a shot and please share feedback — here or on Discord (https://marimo.io/discord).

P.S. This is not our commercial product, this is really just for our community.

[1] https://github.com/marimo-team/marimo [2] https://github.com/googlecolab/colabtools/issues?q=is%3Aissu...

user:	lahuard
created:	June 2, 2025
karma:	5