spool is a local-first prototyping canvas for websites, apps and presentations. Your agent writes live TSX frames into your repo, and you play the flows between them like a real app.
Free on your Mac, with the source on GitHub. Spool Cloud for teams, from $16 a seat →
The Agent tab inside spool, or Claude Code in a terminal, Claude or Codex. Each writes TSX into design/, and the canvas draws each file as it is saved.
A link is one line in the frame, so Fair answers like the app it will become. Tap Saturday and the day opens, because fair-now says where that row goes.
design/frames/app/fair-now/frame.tsx
Each slide is a frame at 1280 × 720 and the deck is the flow between them. Present it from spool and the ring moves with you from slide to slide.
Three.js, WebGL and WebGPU work in a frame like any other React. Stilla's speaker is a real model: pick a colour and it changes, go on to the top and the camera follows.
With Spool Cloud, every save reaches the team in about a second, and you see each teammate on the canvas by name.
Freeon your Mac, open source
The canvas, every agent, flows, decks and 3D, in your repo's design/ and kept by git.
$16per editor a month, billed yearly
Plus VAT where it applies.
Team projects that sync in about a second, with everyone on the canvas by name. Editors work in spool on a Mac. Viewers and share links for clients are free, and open in any browser.
14 days free for up to 10 editors, with no card until you pay.
Every save in a team project reaches everyone's copy as real files in their own repo.
See who is on which page, and watch a teammate click through a live frame as they do it.
Send a protected link to a flow. A client opens it in the browser and plays it.
Your team's projects open in any browser, view only, with the same canvas and the same player.
The Mac app keeps itself up to date, and its npm package runs the same canvas from your Mac's terminal.
spool's source is public under the Functional Source License, and each release turns MIT after two years. Read the code on GitHub.