Typora - A minimal Markdown reading & writing app.
Jupyter - Project Jupyter exists to develop open-source software, open-standards, and services for interactive computing across dozens of programming languages. Ready to get started? Try it in your browser Install the Notebook.
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Kajero - Interactive JavaScript notebooks - create good-looking, responsive, interactive documents.
Dillinger - joemccann has 95 repositories available. Follow their code on GitHub.
BeakerX - Open Source Polyglot Data Science Tool