Test the flow, not the rectangle.
Static prototypes fail the moment a user types something unexpected. Master builds a real app in minutes, so the feedback you collect is about the product.
Prompt, click, share, revise — several times a day.
Prompt
Describe the flow you want to test. No component library setup, no boilerplate.
Click through
The preview is a real app — forms submit, data persists, states are real.
Share
Send a link. Testers use it on their own device without installing anything.
Revise
Change it while the feedback is still fresh, then restore any earlier version.
From sentence to a testable screen.
Ask for the flow. The agent builds the screens, the state and the edge cases, and the preview reloads as it goes.
Everything a research session needs.
Interactions, not hotspots
Real inputs, validation and empty states instead of linked rectangles.
One link to test
Share the preview with stakeholders or testers; no accounts required to look.
Versions and restore
Every build is a checkpoint. Compare directions and roll back instantly.
Two directions at once
Remix the project and explore an alternative without losing the original.
Responsive by default
Check desktop, tablet and phone from the preview toolbar before the review.
Promotable
When the prototype wins, it becomes the product — the code is already real.
Keep the winner.
Frequently asked.
Is this throwaway code?+
Only if you want it to be. A Master prototype is a normal React app, so a validated direction can turn into the shipped product.
Can testers use it on their phone?+
Yes. Share the preview link and it runs in any browser, on any device.
Can I try two directions?+
Remix the project to fork it. Both versions stay live and you can compare them side by side.
What about real data?+
Connect the built-in database and the prototype behaves like the real thing — persistence, accounts and all.