Multiplayer code editor system

Project Description

  • Open source code editor for JavaScript, HTML, CSS, and Markdown
  • Support for real-time collaboration
  • Invite collaborators over LAN or HTTP Tunneing
  • Focus on instant feedback during development
  • Core component of VizHub next generation editor



  • Create a usable alternative to VSCode + Live Share for use in front end development
  • Enable developers to “enable” the VSCode editor on their projects via NPM
  • Have the npm run edit command start a local server
  • Develop a sidebar panel that lists files in the file system
  • Develop a code editor panel using CodeMirror that lets users navigate between files
  • Have the server auto-save files to disk when changes are made
  • Synchronize code edits across multiple clients using Operational Transform (JSON1 and ShareDB)
  • Ensure that the editor works well on top of the Vite dev server
  • Dogfood the product to identify ways it can be improved
  • Iterate based on feedback
  • Share the project with the world

Prior Work

This project is heavily based on prior work done in the VizHub Project. VizHub already has a code editor component that supports real-time collaboration. However, this was built using older versions of CodeMirror (version 5) and operational transform (json0. Various prototypes were built as a proof-of-concept for building a similar editor using the latest CodeMirror (v6) and the latest operational transform library for ShareDB (json1).

There is a working demo at https://vizhub.community/ci/viz1 (try it in multiple tabs to see the real-time sync), whose source code lives at https://github.com/vizhub-core/vizhub/tree/main/vizhub-v3 . Also we’ll draw from this standalone CodeMirror6 collaboration demo: https://github.com/vizhub-core/vizhub/tree/main/vizhub-v3/vizhub-codemirror. For this project we’ll port components out of that demo so that the code editor is totally independent and isolated from anything specific to VizHub.


It will look something like this ☝️ once it’s working. This VZCode project will draw inspiration (and possibly implementation) from the existing open source editor component of VizHub, and various prototypes that have been done with CodeMirror6.


See also VZCode Kanban Board.

February 2023

  • Get the first version working, including:
  • ShareDB server
  • Auto-save
  • Edit the content of multiple files (no support for folders initially)

March 2023

  • Make it usable, including:
  • UX for adding new files, renaming files, deleting files
  • Implement presence (the ability to see the cursors of others in real time)
  • Test out how it works using tunneling services such as NGrok

April 2023

  • Add support for nested directories, including:
  • Develop a tree-based sidebar UI allowing directory navigation
  • Dogfood the product and try to collaboratively develop something, maybe a data visualization
  • Gather feedback from early users and iterate based on that
  • Publish a YouTube video presentation of the work to date


  • Curran Kelleher
  • Students from RPI RCOS
  • Additional external collaborators, TBD
  • Drop a line to Curran if interested in collaborating on this!



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