A team on one screenplay, without stepping on each other. A lead invites co-writers, each forks a frozen draft and writes a pass, and the lead weighs the passes into a new draft — one change at a time.
It is deliberately asynchronous. Nobody types into the same document at the same time, nothing is merged on a server, and nothing you did not choose ever reaches your draft. Co-writing is the review feature grown a second direction: passes come back the way notes do, and the lead pulls in what they want the way they revert a change.
If you have read Drafts and notes, you already know most of the machinery — frozen drafts, Compare, the marks on the page. This is the same machinery pointed at more than one writer.
The lead freezes a draft and invites a co-writer. The co-writer forks that draft into a workspace of their own, writes a pass, and submits it — which freezes it and sends it back, while they carry on writing. The lead reconciles the passes that have come in, choosing per block what to take, and publishes the result as a new draft. Each co-writer then sees what became of what they sent, and carries the new draft into their work.
Collaboration ▾ → Invite a co-writer… Type an address and, if you like, a word about where to start. They get an email with a link.
You need a frozen draft first. A co-writer forks one, so with none there is nothing to invite them into — the same rule asking for notes keeps. Freeze a draft, then invite.
The invitation names an address, not a secret link: your co-writer signs in as that address, and that is the whole of it. There is nothing in the link to leak, and nobody but the person at that address can take it up.
Collaboration ▾ → View passes… lists every pass a co-writer has sent — who wrote it, when, how many pages, and which of your drafts it was built on (based on Draft 3 · current, or · 2 drafts old, so a pass whose author needs to catch up says so). It is a history; the one way in is the button above it.
Review passes… opens every co-writer's latest pass in the compose view — the same marked page as Compare, with a list of the changes down the side. There is no blind accept: a pass is taken in one change at a time, here, where you can read it.
Applying moves your working copy; it does not reach your co-writers. They compare against your frozen drafts, never your live one — so after a reconcile, the app asks whether to publish a new draft. Until you do, what you accepted is invisible to them and their sent changes read as still pending.
This is the same reason a review is sent as a frozen draft: a moving target is impossible to reconcile against. Reconcile, then freeze, and the round is closed — the verdict you just made is one your co-writers' Compare can read.
Collaboration ▾ → Co-writers… lists the team, with Remove on each. Removing closes the door — nothing more can be submitted — but the passes they already sent are drafts of yours and stay.
At their end, a pass with work behind it is not yanked away: the project moves to an Archived section of their sidebar and turns read-only, with Export still on the toolbar, so they can keep a copy of what they wrote. Their pass already lived in their browser; archiving it exposes nothing new.
An invitation appears in your sidebar under its own heading. Open it and pick the frozen draft to fork; from then on you have a workspace that behaves like a project of your own.
It is quarantined, on purpose. A pass is not one of your screenplays and never becomes one: it is not saved to your library and never backed up to your account. What you write here goes to the lead when you submit it, and nowhere else.
The lead reconciles and publishes, and word reaches you — a New draft · see what changed notice by your account menu, and the co-write bar's Compare button lit. Either opens the same screen.
Down the side is what became of what you sent, each change marked:
The lead accepts a whole pass but may compose only some of its changes, so an un-picked change from an accepted pass reads as rejected, not accepted — the truth is the draft, not the stamp. The ↗ on any card jumps the page to that change's line and flashes it.
The page shows the changes the new draft carries against your working copy — the lead's incoming edits, marked in place, so you read what actually moved rather than a wall of your own lines. Your own kept work stays plain, because you already know what you wrote. Marked and Clean switch between the marked-up page and the draft you would carry over with the marks taken off, and a colour key names the marks along the bar.
Carry over makes your working copy the new draft, with your pending changes and everything you wrote since submitting laid on top, plus any rejected change you ticked to re-submit. Accepted changes are already in the draft, so they are never laid down twice.
Nothing is frozen and you keep writing — carrying over is coming up to date with the lead, not sending anything. Your next submission goes out from the new draft, so the lead never has to untangle a pass built on a draft two rounds old.
A shared cursor — two people typing into one document while a server stitches their keystrokes together — is a different product, and one that loses work in ways nobody can see. Fabula One backs up; it does not sync. Every hand-off is a whole, frozen pass, and the only thing that ever combines two people's work is a person choosing, in the open, one change at a time.
The cost is that you take turns rather than write at once. In exchange, no edit is ever silently overwritten, every version is kept, and a disagreement is a decision somebody made rather than whichever save landed last.