Lyubomyr B.

Senior iOS & macOS VPN Engineer | NetworkExtension | Xray, Libbox, Go

I focus on building reliable software and solving difficult technical problems efficiently. I specialize in building and stabilizing VPN applications for iOS and macOS using Swift — and in hybrid stacks where a Go networking core powers the packet tunnel (gomobile, DNS interception, UDP/TCP relay) alongside Network Extension on the Apple side. My work focuses on the parts that are hardest to get right: NetworkExtension integration, tunnel lifecycle, lock/sleep recovery, kill switch and on-demand behavior, reconnect flows, and platform-specific networking edge cases under iOS memory and background limits. I also work with Xray and Libbox integrations and have hands-on experience with VPN technologies including OpenVPN, IKEv2, IPSec, WireGuard, VLESS, VMess, and Shadowsocks. Recent delivery: stabilized a production parental-control VPN app — domain and image filtering, MITM inspection, DNS hardening (including DoH fallback), and fixed intermittent "no internet while VPN is on" after extended device lock. Shipped stable TestFlight builds with production-ready, root-cause fixes. I help teams resolve difficult issues around race conditions, state management, reconnect behavior, and long-running reliability across Apple platforms (iOS, macOS, tvOS). I'm a strong fit for projects that need more than basic mobile development — especially apps where connection stability, traffic filtering, native platform behavior, and deep debugging are critical. What I can help with: • iOS and macOS VPN development (NetworkExtension, Packet Tunnel) • Swift + Go hybrid VPN cores (tunnel, DNS, stability) • Kill switch, on-demand, reconnect, and tunnel management • Parental control / content filtering (domains, HTTPS image inspection) • Debugging lifecycle, networking, and memory-pressure issues • Stability, performance, and production hardening I focus on production-grade reliability — stable tunnels, correct filtering under edge cases, and fixes that hold up in real-world use (lock/sleep, reconnects, memory limits), not temporary workarounds.