Newsletter 2

Newsletter 2

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Hi! 👋 You’re reading the second marimo newsletter. If you’re new here: welcome to the marimo community!

Since the last newsletter landed in inboxes one month ago, we’ve shipped many new features and welcomed several new members to our Discord server.

This newsletter is about a new feature that we’re especially excited about: It’s now possible to run marimo entirely in the browser – no backend required!

Announcing our online playground for marimo

We’ve created an online playground for marimo: try it out by opening our tutorial notebook or creating a new marimo notebook at

Our playground is powered by two emerging technologies. WebAssembly (or “WASM”), a binary instruction format that can be executed by modern web browsers, and Pyodide, a port of CPython to WASM. WASM makes it possible for web browsers to execute Python, C/C++, and Rust, eliminating the need to call out to remote machines. For this reason, marimo notebooks that run entirely in the browser are called WASM notebooks.

WASM notebooks are extremely easy to tinker with and share. We’ve even made it possible to seamlessly open local notebooks in our playground, to create shareable permalinks from within the playground, and to embed WASM notebooks or apps in static web pages: read our guide on WASM notebooks to learn more.

We’ve created a few example notebooks to jumpstart your imagination. There’s one that trains a tiny neural network, another that visualizes Bayes’ Theorem, and another that plots attractors of dynamical systems. One of our community members even published a QR code generator as a WASM notebook.

When you take a moment to think about all this, it’s really quite magical . You can use any pure Python package, as well as a number of packages for scientific computing, including Pandas, NumPy, SciPy, matplotlib, and scikit-learn, entirely in the sandbox of your web browser – without installing Python on your machine and without paying for infrastructure.

We’re on a mission to make computing more accessible

We believe that WASM notebooks hold enormous potential for making computing more accessible. With WASM …

  • anyone can create and share live notebooks, without having to pay for infrastructure
  • students can get started with Python instantly, without having to set up a development environment
  • library developers can embed interactive coding environments in documentation — we’ve done this throughout our own API docs
  • authors can publish interactive blog posts and computational tools as part of static web pages.

We want to hear from you. We have ideas on how to make WASM notebooks more useful — e.g., we’d like to make it easier to work with auxiliary code and data files. Most of all, though, we’d like to learn what would be most useful to you.

Some of you have expressed interest in a hosted product built around WASM notebooks that’s more turn-key than our playground. If that’s something that interests you, or if you have other ideas, please reach out to me at

Finally, we’d love to hear about any WASM notebooks you make! Tag us on Twitter, or share your notebook on Discord.

Happy building!