Feature
Build working prototypes with AI
In AppSprint's Prototype step, each person describes what people should be able to try, and the AI builder returns a working prototype as one self-contained HTML file. It can build a web app, a web game or a visual design. The team then reviews all the prototypes anonymously and refines the chosen one together. The builds are clickable demos with no backend, not production apps.
What the builder makes
- Web App: a clickable app with several views inside one file.
- Web Game: a playable 2D or 3D game that runs on engines built into AppSprint, with no outside dependencies.
- Design: AI-generated images, short video clips of 8 seconds, and an image slide deck.
- Every build comes back with a title, a short summary, three highlights and the HTML itself.
- Each build is a single HTML file with inline CSS and JavaScript. External libraries, fonts, APIs and network calls are not allowed.
How a build works
Describe what people should be able to try
Write in plain language. You can attach up to 3 images and 5 files. Up to 2 web addresses in a prompt are captured as screenshots for reference.
Wait for the result
The screen shows status text while the AI works, then the finished prototype. Code is not streamed to the browser as it is written.
AppSprint checks the build
The result is validated in a sandbox. If it fails, the builder makes one automatic repair pass before showing it.
Try it and ask for changes
The preview has a desktop and mobile toggle. Follow-up prompts are applied as targeted edits, with a full rebuild as the fallback.
Choose what to present
In the solo Prototype step each person can build up to 2 projects and picks one to present. Your version history keeps 10 versions and lives only in your browser.
Solo builds and the shared build
In the Prototype step, everyone builds alone and the results go to an anonymous review with the builder hidden. In Refine Together, the team works on one shared prototype: only the decision-maker prompts the AI, and teammates send anonymous suggestions. AI teammates never build.
Models and cost
The builder can run on models from OpenAI, Anthropic (Claude) and Google (Gemini), at three quality levels: Fast, Balanced and Best. The default is a light Gemini model on Fast. Larger models on Best use many more credits per build.
The host pays for all AI usage in the room. New accounts get 5,000 trial credits with no card. See pricing.
Limits worth knowing
- No backend, database or real APIs. Data you enter into a prototype is not saved to a server.
- No frameworks or external libraries. For the real build, take the build brief (PRD) and handoff package to developers or an AI coding tool.
- Slide decks from Design mode export as image-only .pptx files with no editable text.
Which templates include it
The solo Prototype step is in the One-Hour Sprint (20 minutes), the Focused Product Sprint and the Full Product Sprint (45 minutes). Team Vibe Coding skips solo builds and starts from a blank shared builder.