marimo is a San Francisco company building an open-source reactive Python notebook that replaces the error-prone JSON of Jupyter with pure Python files. Cells form a dataflow graph, so changing one variable automatically re-runs the cells that depend on it - notebooks are reproducible, git-friendly, deployable as apps, executable as scripts, and can even run entirely in the browser via WebAssembly. Founded in 2022 by Akshay Agrawal and Myles Scolnick, marimo raised a $5M seed in 2024 and joined CoreWeave in October 2025 while keeping the notebook free and permissively licensed.
Akshay Agrawal is the co-founder and CEO of marimo, an open-source reactive Python notebook stored as plain Python files so it is reproducible, git-friendly, runnable as a script, and deployable as an app. A Stanford PhD advised by Stephen Boyd, he co-built version 1.0 of CVXPY, created the embedding library PyMDE, and worked on TensorFlow 2.0 at Google Brain. marimo has grown past 20,000 GitHub stars and raised a $5M seed round led by AIX Ventures, backed by figures including Jeff Dean, Wes McKinney, and Clement Delangue.