What makes it hold together
Collaborative editing is easy to demo and hard to get right. These are the parts that decide whether it survives two people and a flaky train connection.
Conflict-free by construction
Edits merge through a CRDT, not a lock or a last-write-wins race. Two people typing on the same line both keep their work, and every client converges on the same text.
Cursors you can follow
Live carets and selections, each in their author’s colour, with names on hover. You can see what someone is about to change before they change it.
Run it, don’t describe it
JavaScript, Python, Java, C and C++ execute in a sandboxed container with CPU, memory and wall-clock limits. Output and exit code land in the panel below the editor.
An assistant that read the file
Explain, debug, improve or test. The request carries the document as it is right now, including the edits your colleague made four seconds ago.
Private until you decide
Projects start private. Share by link when you want to, grant editing separately from reading, and revoke either without moving the code.
Survives a bad connection
Documents persist server-side and reconnect with backoff. Close the tab mid-sentence and the room still has your sentence.
Open a file. Send the link.
No install, no extension, no screen share. The other person sees your cursor within a second of clicking.
Create your first project