DeltaConnect
The companion app for a home-security provider — arm, monitor and react from anywhere.
Sole iOS engineer (freelance) · Freelance engagement · Shipped
Overview
DeltaConnect is the customer app for a Kosovar home-security company: system status, arming and disarming, and real-time alarm alerts, replacing a workflow that used to run on phone calls and physical panels.
Problem
The company's customers had professional monitoring but no direct visibility: checking whether the house was armed meant the wall panel or a phone call. An alarm event reached them as fast as a human operator could dial.
Solution
A mobile app that treats the security system's state as the product: a glanceable home screen answering 'is everything okay?' in one look, one-tap arm/disarm, and push alerts that arrive the moment an event fires rather than minutes later.
Architecture
SwiftUI with MVVM, integrating the provider's security backend over REST and Firebase for messaging and diagnostics.
State handling built around a confirmed-state model: the app displays what the security system has acknowledged, never what the user merely requested — with in-flight commands rendered explicitly as pending.
Engineering challenges
An alarm app must never lie
Optimistic UI is the norm in consumer apps, but showing 'armed' before the system confirms it is a safety failure, not a UX nicety. Every mutating action renders its pending state honestly and reconciles against the backend's acknowledgment, including the failure paths.
Alerts that survive the real world
Alarm pushes compete with focus modes, dead zones and backgrounded apps. Critical events were layered — push, in-app state refresh on foreground, and server-side escalation — so a missed notification never meant a missed alarm.
Lessons learned
- In safety-adjacent UI, the honest slow answer beats the fast wrong one — design the pending states first.
- Freelance clients don't buy architecture, they buy outcomes — but the architecture is why the outcome still works two years later.
Tech stack
- Swift
- SwiftUI
- MVVM
- Firebase
- REST APIs
- Push notifications