Cross-Platform VPN App Development

I need a full-featured VPN application built for Android, iOS, and Windows. The core experience must feel identical on every platform: users pick a server, hit connect, and enjoy a secure, leak-free tunnel.

Essential functionality
• Server list that can be refreshed remotely, sorted by real-time ping, and filtered before connection
• One-tap Server selection plus an Auto-connect option that obeys user rules (on app launch, on unsafe Wi-Fi, etc.)
• Always-on Kill switch that survives network changes and guarantees zero traffic outside the tunnel
• DNS management inside the app so I can point users to custom resolvers or a local blocker

Protocol support
OpenVPN (TCP & UDP), WireGuard, L2TP, and an HTTPS Proxy mode must be selectable per server or globally. Switching protocols should not force users to re-enter credentials.

Deliverables
1. Store-ready builds: APK, TestFlight IPA, and a Windows installer
2. Complete, well-commented source code with build instructions
3. Lightweight branded UI (logo, colour palette, icons)
4. Admin guide explaining how to add or retire servers, edit DNS defaults, and trigger app updates
5. Two-week post-delivery bug-fix window

Acceptance criteria
The app connects on every listed protocol, maintains the tunnel through sleep/roam events, enforces the kill switch, and displays accurate ping values. Leak tests (IP, DNS, WebRTC) must all pass.

If your previous work already integrates WireGuard and OpenVPN, the hand-over will be smoother, but clean, maintainable code is my top priority.