Matrix Highlight

A decentralized and federated way of annotating the web based on Matrix.
Watch a quick demo video, or read the introductory post.
If you’re on Matrix, come chat with us at



  • Current: Create and send website annotations over Matrix.
  • Current: Store data in a decentralized and federated manner.
  • Current: Share highlights with other users, including those on other servers.
  • Current: Group annotations together and create multiple annotation groups
  • Planned: Use Matrix’s End-to-End encryption to ensure the secure transmission and storage of highlight data.
  • Planned: Leverage the new m.thread MSC to allow users to comment on and discuss
  • Planned: Use something like ArchiveBox to cache the current version of a website and prevent annotations from breaking.
  • Planned Highlight PDFs in addition to web pages.

See Also

Also check out Populus, which is a tool in similar spirit, but with a focus on annotating files.


The project is a handful of React applications written in TypeScript. It’s sufficient to run:

yarn install
yarn webpack

An (unpacked) extension will be available in dist/. Then, you can follow the [Google guide] to
install the unpacked extension in Chrome or Chromium.