Performance Engineer

measurement, analysis, and optimization of Proton VPN's end-to-end performance, across clients, platforms, and global infrastructure. You'll help ensure that every connection is fast, stable, and private, regardless of where the user is or what network they're on. What you will do Design and own Proton VPN's performance framework, defining metrics and KPIs that reflect the real-world experience of users (time-to-connect, throughput, latency, stability, reconnection rates, etc.). Develop distributed testing systems that simulate real network conditions, including low bandwidth, packet loss, and high-latency scenarios. Continuously measure and analyze performance across platforms (desktop, mobile, backend) and regions to identify bottlenecks and regressions. Collaborate with backend, R&D, and client teams to optimize protocol handling, connection setup, routing, and encryption performance. Create dashboards, reports, and automated alerts to track global performance health. Contribute to the design of resilient connectivity strategies that adapt dynamically to variable network conditions. Serve as the performance champion within the engineering organization, mentoring others and driving a data-driven performance culture. Job requirements Technical Skills 5+ years of experience in performance engineering or systems QA, ideally in networking, VPNs, or distributed systems. Knowledge of network protocols (TCP/IP, UDP, TLS, WireGuard, debugging, manipulating, and performance profiling tools. Proven ability to analyze latency, throughput, and stability metrics across multiple layers (client, OS, transport, application). Proficiency in Python (or similar scripting language). Familiarity with network emulation and simulation tools (e.g., tc/netem, iperf, IPTables/nfTables...). Experience with monitoring and observability stacks (Grafana, Prometheus, Loki) and CI/CD pipelines. Cross-platform experience with Linux, macOS, Windows, Android, and iOS preferred. Bonus points for Experience with Rust/C/C++/System development Soft Skills Analytical and methodical, yet creative in solving complex performance problems. Comfortable working with uncertainty and

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