Rating: 4.7/5
Best For: Data scientists, researchers, and Python developers who want reactive, reproducible notebooks
Pricing: Free and open source
Verdict: marimo is the best Jupyter alternative available in 2026. Period. The reactive execution model eliminates the hidden state bugs that plague traditional notebooks. Every notebook is stored as pure Python, making it git-friendly and executable as a script. With 19.8K GitHub stars and endorsements from the founders of Kaggle, Pydantic, and Django, marimo has earned its position as the next-generation Python notebook. And it is completely free.
marimo is an open-source reactive notebook for Python that fundamentally rethinks how interactive computing should work. Unlike traditional Jupyter notebooks where cells can be run in any order and hidden state causes reproducibility nightmares, marimo treats notebooks as dataflow graphs. Run a cell or interact with a UI element, and marimo automatically runs all dependent cells -- keeping code and outputs perfectly synchronized at all times.
Every marimo notebook is stored as a pure Python file (not JSON like Jupyter), which means you can version control it with Git, execute it as a script from the command line, import it as a Python module, and deploy it as an interactive web application. This versatility is what separates marimo from incremental improvements to the Jupyter ecosystem -- it is a fundamentally different approach to interactive Python.
The project has accumulated 19.8K GitHub stars and is downloaded hundreds of thousands of times per month. It is used by enterprises including Cloudflare, Shopify, and BlackRock, as well as research institutions like Stanford, Johns Hopkins, and Princeton. Anthony Goldbloom, the founder and CEO of Kaggle, called marimo one of the few technologies that have been truly transformational for him. Samuel Colvin, the creator of Pydantic, said marimo solves all his frustrations with Jupyter elegantly.

The core innovation. When you change a cell, marimo automatically identifies and reruns all cells that depend on it. There is no hidden state, no stale outputs, no out-of-order execution bugs. This reactive model eliminates the number one source of errors in traditional notebooks.
Notebooks are stored as .py files, not JSON. This makes them git-friendly with clean diffs, executable as scripts, importable as modules, and deployable as web apps. One file format, five use cases.
Built-in sliders, dropdowns, tables, file uploads, and selectable plots that reactively update dependent cells. Build interactive data exploration tools and dashboards directly in your notebook.
Write SQL queries directly in marimo cells with support for DuckDB, SQLite, PostgreSQL, and MySQL. SQL results integrate seamlessly with Python code in the reactive dataflow graph.
Built-in copilot-style autocomplete and AI assistance directly in the editor. Generate code, fix errors, and explore data with AI support that understands the notebook context.
Deploy any marimo notebook as a shareable web application with a single command. No separate deployment framework needed -- your notebook IS your app.
Run pip install marimo or uv pip install marimo to install.
Run marimo edit to open the editor in your browser. Create cells and start coding -- changes automatically propagate.
Use built-in UI widgets like sliders, dropdowns, and interactive tables. They automatically trigger reactive updates in downstream cells.
Execute with marimo run notebook.py to deploy as a web app, or python notebook.py to run as a script.

marimo is completely free and open source under the Apache 2.0 license. There are no paid tiers, no feature gates, and no usage limits. The full platform -- including reactive execution, interactive widgets, SQL support, AI features, and app deployment -- is available to everyone at no cost.

| Alternative | Best For | Price |
|---|---|---|
| Jupyter Notebook | Traditional interactive Python | Free |
| Google Colab | Cloud notebooks with free GPUs | Free / $9.99/mo |
| Observable | JavaScript reactive notebooks | Free / $12/mo |
| Hex | Collaborative data workspaces | Free / $24/mo |
marimo earns a 4.7/5 and represents the most significant advancement in Python notebooks since Jupyter itself. The reactive execution model is not just a nice feature -- it fundamentally solves the reproducibility crisis that has plagued computational notebooks for years. The fact that it is completely free and open source makes the recommendation easy: if you work with Python for data science, research, or application development, you should try marimo.
The only reasons not to switch immediately are deep investments in Jupyter-specific extensions or workflows that depend on out-of-order execution (which marimo intentionally prevents). For everyone else, marimo's combination of reactive execution, pure Python storage, interactive widgets, SQL support, and one-command app deployment makes it the best notebook experience available.
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Yes. marimo is designed as a next-generation alternative to Jupyter. It addresses Jupyter's core limitations -- hidden state, JSON storage, lack of reproducibility -- while adding reactive execution, interactive widgets, and app deployment.
Yes. marimo provides a conversion tool that transforms .ipynb files to .py marimo notebooks. Some manual adjustment may be needed for notebooks that rely on out-of-order execution.
Yes. marimo is fully open source under the Apache 2.0 license. All features -- including reactive execution, interactive widgets, SQL support, AI copilot, and app deployment -- are free with no usage limits.
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