Using the GO Scanner
Short answer
Head to scanner.guestlistonline.com on any phone or tablet and log in with your door-staff account. It is an installable web app, no app store needed.
Head to scanner.guestlistonline.com on any phone or tablet and log in with your door-staff account. It's an installable web app (no app store needed). On iPhone tap the Share icon, then Add to Home Screen; on Android tap "Install app" when prompted. Once installed it runs fullscreen like a native app and uses your camera for instant QR scanning.