Senior Site Reliability Engineer - VPN Service | NordVPN at Nord Security

The world’s most advanced VPN, and a whole lot more.   If you’re a curious problem-solver who carves their own path, join the team behind Threat Protection Pro, the NordLynx protocol, and the fastest VPN on the planet—tools that put privacy, security, and control back in people’s hands. Your impact? Helping millions take back control of their online security, privacy, and data. NordVPN operates a globally distributed VPN and DNS infrastructure serving millions of users. Your responsibility is the service itself - deploying, managing, and improving VPN nodes worldwide while ensuring every client connection is fast, stable, and secure. You'll work closely with application teams to guarantee smooth client connectivity end to end. Quality and reliability are the job.   Main Responsibilities • Deploy and manage globally distributed VPN and DNS services • Ensure connection quality, stability, and performance across the entire node fleet • Collaborate with application teams on client connectivity and protocol behavior • Optimize VPN service performance — kernel tuning, flamechart analysis, profiling • Manage security posture — firewalls, PKI, certificate lifecycle, hardening • Manage authentication and authorization infrastructure • Own configuration management and automated provisioning of infrastructure • Clear written incident communication and postmortem ownership Core Requirements • Own critical VPN services end-to-end including architecture, scalability, security and monitoring • Deliver OKRs and key commitments within agreed timelines • Write RFCs/ADRs for new features, refactors, etc • Raises engineering quality through standards, design reviews, knowledge sharing and mentorship • Balances reliability, security and delivery speed with strong operational judgment • Advanced networking - VPN protocols, tunneling, routing, DNS • Linux at depth - kernel internals, tuning, module management • Firewall management • Performance analysis - flamecharts, profiling, bottleneck identification • OSI model fluency - L2 through L7, TCP/IP stack, SSL/TLS • Security fundamentals - PKI, certificate management, hardening • Authentication and authorization - RADIUS, access control • Configuration management and automated deployments • Load balancing and failover for distributed services • Docker Bonus Points For • Python programming • C, Rust, or Go - for lower-level service and performance work • Observability knowledge - monitoring, metrics, logging for VPN services • On-demand bare-metal/hardware provisioning • eBPF, strace, and advanced debugging/tracing tools • Virtualization - KVM, MicroVM • Kubernetes networking • Interest in AI tooling - Claude Code, agentic engineering, LLM integrations in engineering workflows Tools You Will Use • Linux kernel and networking stack • SaltStack • Consul • Firewall - nftables • DNS - BIND, dnsdist, Unbound • FreeRADIUS • Vault and PKI infrastructure • MySQL (Percona), Redis • Docker • iPXE Salary Range • Gross Salary 5800-7400 EUR/Month What We Offer Innovate with industry leaders Work alongside global experts to build world-leading cybersecurity tools, impacting millions of users around the world. Learn & grow Boost your skills via our extensive training programs (online and offline) & other resources. Benefit from mentorship and career-switch opportunities to grow within the company.  Work in a next-gen Cyber City office Thrive in our bustling office, featuring ergonomic workspaces, modern meeting rooms, engaging events, and specialty coffee to fuel your day. Hybrid work Enjoy the flexibility with 3 office days and working from home for the remaining 2. Work from anywhere Recharge with a change of scenery – choose work from any location when you feel a need to power your creativity and drive.   Physical well-being Boost your health with free-of-charge 24/7 gym access, onsite and online workouts, and consultations led by in-house Physical Well-Being experts.  Mental & emotional health Nurture your mind with free psychologist consultations, dedicated mental health events, and premium access to top-rated wellness apps like Calm, Headspace, and Mindletic. Premium healthcare Receive private health insurance giving you peace of mind for your health needs. Extra days off Enjoy additional vacation days off as you grow with us. Plus, get extra days for sick leave, special occasions, or parenting needs.   Joyful moments – special treats Celebrate life’s big moments with special gifts from us on your birthday, anniversary, and other major events, such as weddings or the arrival of a new family member.   Company events & team-building Experience iconic Nord Security celebrations, team-buildings, and knowledge-sharing events, nurturing bonds that fuel our success. Workation Embark on a legendary company getaway abroad, filled with exciting activities, live concerts, engaging workshops, and epic time together. Kindly refer to our Privacy Notice for Recruitment Candidates for comprehensive information regarding our data handling procedures throughout recruitment processes: [Upgrade to PRO to see link] We expect all candidates to provide accurate and complete information during the recruitment process. While limited use of AI tools to refine application materials is acceptable, candidates remain fully responsible for ensuring that their submissions reflect their own qualifications, skills, and experience. Any failure to do so may negatively affect participation in the recruitment process. If broader AI assistance is allowed for a particular role or stage, we’ll let you know in advance. By submitting your application, you acknowledge that it may be processed using automated tools for evaluation purposes. As part of our recruitment process, we may use an AI-based application review tool to help assess applications based on skills and experience relevant to the role. This technology is used to support - not replace - human decision-making, and every application is ultimately reviewed by a recruiter. If you would like more information about how AI is used in this process or wish to exercise your rights under applicable data privacy laws, please contact us at [Upgrade to PRO to see contact]. Should you prefer to opt out of the automated evaluation, please submit your application directly to [Upgrade to PRO to see contact].