Building
Live preview
Try your app while it is being built, check how it looks on a phone, and catch issues before you publish.
Last updated September 21, 2026
Use the preview like a user
Open every page in the header. Submit forms. Try the flows you asked for. The preview is the source of truth for whether the app matches the prompt.
Phone and desktop
Resize the preview or use the device toggle when it is available. Mobile polish is part of the quality bar — if a layout breaks at phone width, say so in chat.