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Please note: Iodide is no longer under development, nor being actively maintained.

New PRs and issues are unlikely to be reviewed, and bugs are likely to go unfixed. We hope that future projects may be able to learn something from our experiments, so as of September 2020 we have no plans to take down the demo server at Nonetheless, should not be used for important work, as it may be shut down in the future.

Note that the pyodide project (python-on-webassembly) continues and is unaffected by this change. For another take on interactive, client-side notebooks, you may also be interested in the Starboard Notebook which provides some of the same capabilities as Iodide and is in active development.

Huge thanks to our community for your support and interest over these last few years!

CircleCI Join the chat at codecov

The Iodide notebook

View source for science

Try it in your browser right now!

Today, sharing scientific results is easier than ever. You can email a PDF, write up a Google doc, or post to your blog. You can embed plots, data tables, and even interactive visualizations. But what if you want people to be able to replicate and extend your results -- to take your results and “view source” to see how you arrived at your conclusions? Or even hack and remix them to ask their own questions?

To do that now, you typically have a couple of options. You could send your code alongside your nice, clean PDF or blog post, allowing you fine-grained control over your presentation, but that requires you to separate your presentable results from your code and to manage multiple files. Alternatively, you could share your results and code bundled together in a notebook format that mixes code with write-up; this has the advantage of keeping your code and results closely tied together, but the presentation can get a bit unwieldy, especially if you want to share your results with a less technical audience. And in either case, sharing your code will only allow your collaborators to replicate and extend your results if they are first able to replicate your whole setup -- if they can run your code with the same libraries, the same data, and the server access.

If only there was a technology that was great for presenting documents and visualizations, that allows code to run anywhere with zero setup, and that all scientists and citizens had access to...

Luckily, that technology already exists: the web browser.


Iodide is a modern, literate, and interactive programming environment that uses the strengths of the browser to let scientists work flexibly and collaboratively with minimal friction. With Iodide you can tell the story of your findings exactly how you want, leveraging the power of HTML+CSS to display your results in whatever way communicates them most effectively -- but still keeping the live, editable code only one click away. Because Iodide runs in the browser you already have, you can extend and modify the code without having to install any software, enabling you to collaborate frictionlessly.

And thanks to WebAssembly, working in the browser doesn't mean that you're restricted to working in just JavaScript. Via the Pyodide project you can already do data science work in the browser using Python and the core of the Python science stack (Numpy, Pandas, and Matplotlib). And that's just the start. We envision a future workflow that allows you to do your data munging in Python, fit a quick model in R or JAGS, solve some differential equations in Julia, and then display your results with a live interactive d3+JavaScript visualization... and all that within a single, portable, sharable, and hackable file.

Our focus is on delivering frictionless, human-centered tools to scientists. You can read more about our core principles below. If this vision resonates with you, please consider contributing to the project!

Visit to see example and demo notebooks, and to learn more!

For information on developing and contributing to iodide, please see our documentation.

PS: We've got a few other ideas about how to make in-browser workflows as ergonomic for scientific tasks as possible, including

  1. using modern JS transpilation tools to extend JS syntax for numerical computing -- just enough for matrix operations, operation broadcasting, n-dimensional slicing, and a few other basic scientific computing needs;
  2. compiling best-in-class C/C++ science libraries (and runtimes!) to Webassembly and wrapping them in ergonomic JS APIs.

If either of those projects appeals to you, please reach out!

Get in touch

Please feel free to join our Google group to contact us and keep up with what we're working on.

You can also chat with us on Gitter.


The Iodide code is shared under the terms of the Mozilla Public License v2.0. See the LICENSE file at the root of the repository.