Principal Systems Engineer, FL

About Us At Cloudflare, we are on a mission to help build a better Internet. Today the company runs one of the world’s largest networks that powers millions of websites and other Internet properties for customers ranging from individual bloggers to SMBs to Fortune 500 companies. Cloudflare protects and accelerates any Internet application online without adding hardware, installing software, or changing a line of code. Internet properties powered by Cloudflare all have web traffic routed through its intelligent global network, which gets smarter with every request. As a result, they see significant improvement in performance and a decrease in spam and other attacks. Cloudflare was named to Entrepreneur Magazine’s Top Company Cultures list and ranked among the World’s Most Innovative Companies by Fast Company. At Cloudflare, we’re not looking for people who wait for a polished roadmap; we’re looking for the builders who see the cracks in the Internet that everyone else has simply learned to live with. We value candidates who have the instinct to spot a "normalized" problem and the AI-native curiosity to create a solution using the latest tools. Our culture is built on iteration, leveraging AI to ship faster today to make it better tomorrow, while ensuring that every improvement, no matter how small, is shared across the team to lift everyone up. If you’re the type of person who values curiosity over bureaucracy, and that AI is a partner in solving tough problems to keep the Internet moving forward, you’ll fit right in. Available Locations: London or Lisbon The Team Cloudflare's Front Line (FL) group operates the world's largest web server, which processes over 120 million HTTP requests every second. We are the guardians of Cloudflare's core infrastructure. As part of the Platform team , you will play a pivotal role in evolving this system. We are a team of senior engineers and architects building and maintaining a web proxy platform that is not just performant but also offers exceptional developer ergonomics for over 20 other teams. Our entire codebase is written in Rust . The Role As a Senior Engineer/Architect on the Platform team, you will be instrumental in building the next generation of our core web server. This is more than just maintaining a system; it's about innovating and building a platform that empowers teams across the company. You will coordinate efforts across multiple teams to design, build, and deploy new features that enhance the availability, safety, and reliability of our edge network. This is a unique opportunity to sit at the nexus of Cloudflare's operations, influencing how millions of people experience the internet. Your primary focus will be on building a high-performance platform with a keen eye on operational excellence. This includes defining and implementing clear Service Level Objectives (SLOs) , monitoring key metrics, and managing error rates to ensure a robust and reliable system. What You'll Bring We are looking for seasoned professionals with a strong background in software architecture and distributed systems. Deep expertise in Rust , with a history of building complex, production-grade applications. Strong competencies in computer science , including a solid understanding of algorithms, data structures, and concurrency control. Experience with performance engineering and a proven track record of optimizing high-throughput, low-latency systems. Excellent communication and collaboration skills to drive consensus and coordinate with diverse engineering teams. A passion for continuous improvement in both operations and product development. Bonus Points A deep understanding of web protocols and web servers . Experience with distributed systems architecture . Knowledge of web security issues and industry standards. Familiarity with Prometheus for monitoring and alerting. Most importantly, we're seeking a builder—someone who is excited by the challe ... (truncated, view full listing at source)