Gloworm Festival App
The official app for the UK’s biggest family festival, built to work where the phone mast doesn’t reach.
- 4 weeks
- Both platforms, against a fixed gates-open date
- 20,000
- Visitors across the weekend
- Zero
- Servers, accounts or signal required
The official app for Gloworm Festival, the UK’s biggest family festival, built for its 10th birthday edition at Thoresby Park in Nottinghamshire. Native on both platforms, with no backend and no network dependency: the entire festival guide works in aeroplane mode, in a field, with no bars of signal.
The Challenge
Thoresby Park is rural parkland, and the festival draws up to 20,000 people across the weekend. Put a crowd that size onto a handful of cell masts and mobile data effectively stops working, exactly when a parent needs it, so any app that fetches its schedule from a server is a blank screen in a field.
The app also had to survive a hostile use context (one-handed, in daylight, with a small child pulling at your arm), take child safety seriously on a site with thousands of people, and ship to both platforms against a deadline that could not move, because the deadline was the day the gates opened.
The Approach
Native on both sides rather than a wrapper: SwiftUI on iOS, Kotlin with Jetpack Compose and Material 3 on Android, so each app belongs on its platform.
Offline was treated as an architecture rather than a feature. There is no backend, no API, no database server and no authentication; every artist, performance, zone, map pin, trader and FAQ is compiled into the app from a single canonical content file that drives both platforms. That is what made late line-up changes a one-line edit, and the offline guarantee absolute rather than best-effort.
Family Kit, the child-safety feature, keeps children’s details entirely on the device: nothing uploaded, nothing shared, no account required.
What shipped
- Both platforms delivered in around four weeks against a fixed gates-open date
- Shipped to the App Store and Google Play under the festival’s own identity
- Full guide works in aeroplane mode: no spinners, no retries, no “check your connection”
- 110 artists, 117 performances, 18 zones, 36 map pins and 13 traders, all bundled offline
- Family Kit lost-child card, with children’s data held only on the device
- “My Day” personal schedule with reminders 15 minutes before each starred act
- Dynamic Type, VoiceOver and high-contrast design for reading a phone in direct sunlight
Inside the app
Events & Festivals
Need an app that works where the signal doesn’t?
Both platforms. Around four weeks. A deadline that couldn’t move, because it was the day the gates opened.