A starting prompt
Paste this into the builder and change the names, rules and colours to yours. It produces a working first version; everything after is refinement.
The one feature that matters: the schedule, live
Schedules change. A room swaps, a speaker cancels, a session moves. If the schedule is baked into the app, it is wrong by lunchtime. The prompt loads it from a Google Sheet — the organiser edits a cell and every phone shows the change on next refresh, with an announcement notification if you post one. This is the whole reason to build the app rather than print a PDF.
Personal agenda and reminders
A star on each talk adds it to My Agenda and schedules a notification ten minutes before, with the room name. Attendees stop missing the session they came for, and the agenda screen is the one they keep open all day.
Everything else is a list
Speakers, sponsors, FAQ, code of conduct, Wi-Fi password, nearby food — lists and pages, all from the sheet or typed into the prompt. The venue tab is a floor-plan image (pinch to zoom) and a map button to the address. Do not over-build: attendees open an event app for thirty seconds at a time.
Weddings, festivals, school fairs
Swap the words and the structure holds: a wedding app has a schedule, a "who's who" instead of speakers, a venue tab and an RSVP form; a festival has stages instead of tracks. Describe the event in a sentence and the builder maps it to the same skeleton.
Distribution
Event apps are often installed by a QR code on the badge. Publish on Play as unlisted so the link works without a search, or share the APK directly for a private event. Either way, start a week early — Play review takes a few days for a new developer account.