Welcome to TypeCell! An open source live programming environment. Together, we want to make it a lot easier to build software, and ultimately to understand, build and share knowledge.

• Open Source, cell-based notebook environment
• Same, powerful editing experience as VS Code
• Full TypeScript support! (no weird custom language constructs)
• Reactive Runtime, cells automatically re-evaluate when their dependencies update (learn more)
• Import NPM packages + types just by writing an import statement
• Support for real-time collaboration (using Yjs)
• Runs on top of Matrix using Matrix-CRDT.

Try the Tutorial to get started!

Complete the tutorial to get familiar with TypeCell:

» Interactive introduction

We've written about the main functionality of TypeCell in the manual:

• Notebooks and cells
• TypeScript and exports
• Reactive variables
• Working with user input
• Imports & NPM
• Collaboration

Another good way to learn is to check out some notebooks from our community:

» View demo notebooks

We'd love to hear your thoughts and see your experiments, so come and say hi on Discord or Matrix.

See CONTRIBUTING.md for more info and guidance on how to run the project (TLDR: just use npm start).

TypeCell is organised as a monorepo containing several packages. Directory structure:

blocknote
├── packages
│   ├── common          - Utility functions shared across the codebase
│   ├── editor          - The main React application
│   ├── engine          - The live-code execution engine
│   ├── packager        - Tool to bundle TypeCell notebook apps (WIP)
│   └── parsers         - Helpers to convert to / from TypeCell notebooks
├── patches             - patch-package patches
└── test-util           - Server and data for unit tests

The codebase is automatically tested using Vitest and Playwright.

We build on top of some really great technologies:

• Monaco: the open source editor that also powers VS Code
• Yjs: CRDT for multi-user collaboration
• MobX: for our Reactive Runtime
• Matrix: the backend of TypeCell.org is a single Matrix instance, using Matrix-CRDT to store and collaborate on "documents as chat rooms"
• ESM.sh: for dynamic ESM imports from NPM
• Typescript: for our compiler and language toolkit

TypeCell is proudly sponsored by the renowned NLNet foundation who are on a mission to support an open internet, and protect the privacy and security of internet users. Check them out!