Subsystem 02.6 · 2026
Voom
Ride-hailing — the rider and driver app
The Voom mobile app, designed and built screen by screen for riders and drivers — with calls between them that ring like a phone call, without either side seeing the other’s number.
01What it is
Voom is a ride-hailing platform: one mobile app for riders and drivers, a .NET API and a back office. I designed and built the whole UI and UX of the mobile app, working alongside a strong team at Inspired Tech.
I also owned in-ride calling from end to end: a call rings on a locked phone and is answered from the phone’s own call screen.
02The problem
A ride app gets a few seconds of attention at a time — on a street corner, in a car, one-handed. Every screen has to be obvious at a glance, for two very different users.
And when rider and driver need to talk, the call has to reach a phone that is locked or asleep, and feel like a real phone call — without exposing anyone’s number.
03What I built
- The mobile app’s complete UI and UX: booking and live-ride screens for riders, the driver’s flows, onboarding, payments and profiles — 77 screens in one app for both roles.
- In-ride calling: VoIP pushes signed and sent straight to Apple, the server-side call lifecycle (ringing, accepted, declined, missed), the native call screen on iOS (CallKit) and Android (Telecom), and WebRTC audio.
- Ride chat, Apple and Google sign-in, one-device sessions for drivers and translated push notifications.
04Technology
- Mobile
- ExpoReact NativeWebRTCCallKit · TelecomGoogle MapsSignalR
- Services
- .NET 9EF Core 9SignalRHangfireAPNs VoIP
05Engineering notes
- 01
Ringing a sleeping phone
VoIP pushes go directly to Apple with a token signed on the server; the app has to report the call to the operating system within moments of waking, or iOS stops delivering them. The call lifecycle on the server keeps both sides consistent when one of them never answers.
- 02
A call that looks like a call
Calls use the phone’s own call screen — CallKit on iOS, Telecom on Android — so they can be answered from the lock screen, with audio routed like any other phone call.
06Results
- 77
- screens designed & built
- 2
- roles, one app
- 2
- stores, live
- Live on the App Store and Google Play.
- In-ride calls that ring and answer like real phone calls, on both platforms.