Flutter Developer | Senior

What we're building BlancVPN is looking for a Flutter Engineer | Senior to support the development of the client app as part of a team : alongside developers and owners of related domains (backend/infra)—from Flutter/Dart to native code for iOS/Android/Windows/Linux, platform channels (Pigeon), and integration with network kernels written in Go. The goal of this role is to ensure a client that remains stable in a constantly changing environment — including during blockages, disconnections, channel degradation, and protocol detection — and an architecture that can withstand these challenges through engineering solutions. What we're looking for Core Requirements - Fluency in Russian and English ( B2+ ) - 5+ years of experience in mobile development, with a significant portion spent working with Flutter and on complex production projects - Native development for iOS and Android. Thorough mastery of one platform: custom modules, platform channels, or Pigeon, and system APIs. Proficiency in the other platform for confident coding and debugging - Network layer below the HTTP client. TCP and UDP, TLS, sockets, routing, connection behavior during disconnections and degradation. The network layer is implemented in native code and Go kernels, so experience debugging networks at this level is required - Low-level experience, even if minimal. C or C++, Go, Rust, dart:ffi, cgo, binary formats. Deep system specialization isn’t required; experience with tasks solved outside of Flutter is needed - Ownership and design. End-to-end responsibility for a feature: defining the problem, technical solution, specification, bringing it to release, and tracking post-release metrics. Examples where the candidate designed a non-trivial part of the system. Some features may involve adjacent areas—it’s important to be able to coordinate with backend/infrastructure owners, assist with setting up, reproducing, and diagnosing issues, and drive changes to a successful outcome through collaboration - Debugging and investigation. The ability to get to the root of a problem, even when the cause lies in another layer. Verifying hypotheses with prototypes and making informed decisions when there is no ready-made answer - Testing. Unit, widget, integration, and end-to-end tests. Understanding what to cover with automated tests and what’s more cost-effective to test manually Nice-to-have - Domain expertise: VPN protocols (WireGuard, OpenVPN, Xray, Amnezia), bypassing blocks and DPI - Low-level: binary protocols and custom implementations of protocols based on specifications; experience working under strict memory constraints (extensions, daemons, embedded systems, engines); real-time development from scratch (WebRTC, MQTT, custom protocols on top of WebSocket) - Related Areas: server-side development, Go, Python, Linux nodes, Docker, basic DevOps - Desktop: services and daemons, privilege escalation, installation of system components, OS extensions; OS-level networking (routing, DNS, traffic filtering); system integration (Windows system tray, macOS menu bar icon, autostart and background operation), installers, and build signing - Development infrastructure: understanding how to set up an internal client infrastructure so that testing and delivery contribute to product quality (automated runs, release pipelines, builds and signing for all platforms, update channels, GitHub Actions, Fastlane, Codemagic) - Public footprint: your own packages on pub.dev, open source, articles, low-level pet projects What you'll be doing - Develop the client application: features, architecture, performance, and release stability - Write and maintain native code for iOS, Android, Windows, and Linux where Flutter falls short - Understand connection behavior in real-world networks: disconnections, channel degradation, failover, and operator-specific characteristics - Manage features end-to-end: planning → technical solution → implementation → release → metrics/impact (in collaboration with the team and stakeholders) - Troubleshoot bugs to their root cause, including those not in Dart (in collaboration with related engineers as needed) - Maintain and develop forks of third-party plugins and kernels, ensuring compatibility and predictable behavior What we offer 🌍 Work from anywhere — fully remote (except Russia, Belarus, China, Syria, Iran, Yemen, North Korea, and some other regions). 🗓️ Flexible 5-day week — start when it suits you; loosely aligned to CET . 💻 Full home-office setup — all the equipment you need, on us. 🌴 40 flexible paid days off + paid sick leave. ❤️ Benefits — VHI, wellness, language courses, mental health support and a referral program. 📈 Room to grow — annual development budget + in-person team meet-ups. Stages 👋 Welcome Call 🛠️ Technical Call 🤝 Pre-Offer Call