Principal C Engineer (DDoS Mitigation)

Company Overview

Our client is a leading cybersecurity firm dedicated to protecting organisations' critical applications and networks from sophisticated digital threats. With a global team of over 100 professionals, they deliver enterprise-grade security through advanced technology and proactive defence strategies, including network security, web protection, and Web Application & API Protection (WAAP). The company fosters a collaborative, energetic, and remote-first culture driven by continuous improvement and innovation.

Role Overview

We are seeking an experienced technical leader to head a small, high-impact team responsible for building and scaling a high-performance DDoS mitigation system. This role is a unique blend of hands-on, low-level systems programming and people leadership, offering the chance to work closely with senior technical stakeholders on critical security infrastructure.

Key Responsibilities

• Lead, mentor, and grow a small engineering team, conducting regular 1:1s, performance reviews, and supporting career development.
• Architect and scale distributed, high-throughput software systems that analyse and filter traffic across a global network, partnering with senior leadership on system design and performance tuning.
• Analyse emerging L3/L4 DDoS attack vectors and design innovative mitigation and detection strategies.
• Contribute directly to the development of critical system components in C, balancing delivery timelines with technical debt and long-term performance.

Required Skills & Experience

• 7+ years of systems programming experience in C, with at least 3 years in a technical leadership or mentorship capacity.
• Proven experience building ultra-high-performance, low-latency systems capable of processing millions of packets per second (e.g., using zero-copy, CPU affinity).
• Deep understanding of low-level programming concepts including pointers, memory management, multi-threading, locks, and lock-free data structures.
• Strong debugging and optimisation skills using tools like gdb, valgrind, and strace.
• Excellent communication and interpersonal skills, with fluency in English or German.

Nice-to-Have Skills

• Experience with network programming and protocols (TCP/IP, UDP).
• Familiarity with kernel-level development (e.g., eBPF, XDP, DPDK).
• Knowledge of anycast routing and BGP.