R&D Engineer at PROTON AG

For a junior-level R+D / cybersecurity engineer working on ProtonVPN, you can expect a multi-stage process designed to assess: (1) culture and mission fit with Proton’s privacy-first values, (2) low-level programming skills in C or Rust, (3) strong understanding of operating system internals and networking stacks, (4) practical familiarity with VPN and cryptographic protocols, and (5) ability to reason about complex, system-level problems. A realistic process consists of 7 rounds: an initial recruiter screening, two technical phone/video screens, followed by a 4-round onsite-style loop (often conducted remotely) that includes a 2-hour live R+D technical interview with Wireshark-based packet analysis, a systems and networking design round, a security/protocol deep dive, and a behavioral/culture fit discussion. The emphasis throughout is on practical low-level engineering, system thinking, and how you learn and collaborate, not just on rote theory.[1][3]