How it works
Tell it an idea. Muse Muse builds a working app on Meta's AI, tests it and puts it online at its own link.
Every method below is written up in the Muse Muse docs, Meta's Model API and Muse Code documentation in one place.
Five steps, a few minutes
1. Share an idea
Type it, or drop in photos, screenshots, a sketch, a short video, a voice memo or a PDF.
Files are stored at unguessable links, so anyone with the link can open them. Voice memos are transcribed with Muse Voice Transcribe, and images, video and PDFs go to the model as they are.
In the docs:Image understandingVideo understandingSpeech to textFile handling
2. Get a plan
Spark 1.3 Contributor turns it into a short plan, called a brief.
The brief comes back as strict JSON: the screens, what goes in and comes out, which Meta models the app calls and why, honest limits and a cost per use. If an idea can't be built safely, the brief says so and the build stops there.
In the docs:Structured outputModelsReasoning
3. Muse Code builds it in a sandbox
Meta's coding agent writes the app in its own sealed computer while you watch.
Each build gets its own Vercel Sandbox: a small Linux virtual machine started from a snapshot that already has a starter app and Muse Code installed. Muse Code runs headless (
muse exec --json --yolo) with the brief as its prompt,AGENTS.mdas the project rules and a skill for each Meta model. The firewall blocks everything but npm, Meta's API and Muse Muse. Muse Code only ever holds a stand-in key, and the firewall swaps in the real one on the way out. Every step streams into the build room next to a live preview.In the docs:Muse CodeHeadless modePermissions and the sandboxAGENTS.md and settingsSkills, hooks and subagentsContained execution
4. It tests and fixes itself
The app is checked like a real one, and anything broken goes back to Muse Code.
In the same sandbox: a typecheck, a production build, the app started for real, and a browser test that clicks through the main flow on a phone-size screen. Then Spark 1.3 Contributor judges screenshots of every screen. Problems go back to the same Muse Code session (resumed with
--session-id), for up to 3 fix rounds.In the docs:Launch flagsBrowser-verified web designJudging screenshots
5. It goes live
It gets its own link, a demo video and a spot in the gallery.
Each app is deployed as its own project. It calls Meta's models only through Muse Muse's gateway, with its own token and a daily spending cap, so no API key is ever in the app. Its actions become an MCP connector that the Muse app and other AI tools can call.
In the docs:AuthenticationPricing and rate limitsTool calling
What you get
Its own link
A working app anyone can open on a phone or a computer.
A demo video
A short recording of the app doing its job, ready to share.
Use it from the Muse app
Each app becomes a connector, so the Muse app and other AI tools can use it for you.
Keep improving it
Ask for changes in the build room and it builds a new version.
Good to know
No sign-up and no API keys. Most builds take a few minutes. Apps reach Meta's models only through Muse Muse, which keeps the keys and caps what each app can spend. See the gallery for apps people made, Rebuilds for Meta's older demos rebuilt on today's models, and Usage for every Meta token used.