Senior Software Engineer, Security Rules in London

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 are 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 (UK), Lisbon (Portugal)

About the role

Cloudflare’s Engineers build and operate the software that helps power 25+ million Internet properties and millions of businesses around the world. Across our engineering organizations, we have opportunities for high caliber, curious and empathetic people to take on big challenges and build some of the best skills in the industry. We’re looking for talented team members to help build high-growth products, help scale our expanding network, build tools to improve availability, performance, uptime, and response times, and make systems failure‑resistant and ready-to‑scale.

We are looking for a talented Systems Engineer to join the Security Rules team. You will work on a range of microservices written mainly in Rust. Technologies we use include Docker, Go, PostgreSQL, Redis, Memcached, gRPC, Kafka, Clickhouse and the usual Unix/Linux tools and workflows. We strive to build reliable, fault-tolerant systems that can operate at Cloudflare’s scale. You will join a team of bright, hard-working, and supportive engineers who are passionate about their craft, and you will be comfortable operating in a fast-paced but sane work environment.

As a senior engineer, you will take ownership of complex technical problems, lead projects from design through production operation, and help shape the architecture and reliability of systems that run at Cloudflare’s scale. You will also mentor other engineers, provide thoughtful technical guidance, and help raise the quality of engineering practices across the team. This role may require flexibility to be on-call outside of standard working hours to address technical issues as needed.

What you’ll do

• Design, implement, and maintain the software systems that comprise Cloudflare’s Application Security Product Offering such as Rate Limiting, Web Application Firewall and more.
• Lead technical design and execution for complex projects, helping define architecture, tradeoffs, milestones, and delivery plans.
• Collaborate with internal teams, including security, network engineering, SRE, and product management, to design scalable solutions to difficult technical problems.
• Help raise the technical bar for the team by identifying systemic improvements, reducing operational toil, and influencing long-term engineering direction.
• Review work from your peers throughout all stages of the development lifecycle to ensure high-quality, maintainable code.
• Mentor engineers across the team by sharing technical context, providing thoughtful code and design feedback, and helping others grow in scope and ownership.
• Work with a wide range of technologies and programming languages, including Rust, Go, as well as various databases (SQL and No‑SQL), Docker, and Kubernetes.

Desirable Skills, Knowledge, and Experience

• 6+ years of relevant professional experience with a technology company.
• Strong programming skills in Rust, Go, C++, or a similar systems-level language.
• Demonstrated ability to lead complex technical projects from ambiguity through delivery.
• Experience building and operating distributed systems.
• Strong interpersonal and communication skills, demonstrating empathy, teamwork and a sense of ownership.
• Experience mentoring engineers, reviewing technical designs and providing high-quality code review.
• Experience with monitoring, alerting and debugging high volume production systems.
• Experience with databases (we use PostgreSQL, Clickhouse and Memcached).

Bonus Points

• Experience influencing technical direction across a team or product area.
• Experience improving engineering practices, operational processes, or reliability for production services.
• Experience with modern Unix/Linux development and runtime environments.
• Experience with monitoring and logging tools like Prometheus and Grafana.
• Experience with containerization and orchestration technologies, such as Docker and Kubernetes.

Compensation

For Portugal based hires: Estimated annual salary is between €66,000 - €91,000. The final offer will be inclusive of time exemption, in alignment with the applicable law and collective bargaining agreements.

Equity

This role is eligible to participate in Cloudflare’s equity plan.

Benefits

• Health & Welfare Benefits: Medical/Rx Insurance, Dental Insurance, Vision Insurance, Flexible Spending Accounts, Commuter Spending Accounts, Fertility & Family Forming Benefits, On-demand mental health support and Employee Assistance Program, Global Travel Medical Insurance.
• Financial Benefits: Short and Long Term Disability Insurance, Life & Accident Insurance, 401(k) Retirement Savings Plan, Employee Stock Participation Plan.
• Time Off: Flexible paid time off covering vacation and sick leave, Leave programs, including parental, pregnancy health, medical, and bereavement leave.

What Makes Cloudflare Special?

We’re not just a highly ambitious, large-scale technology company. We’re a highly ambitious, large-scale technology company with a soul. Fundamental to our mission to help build a better Internet is protecting the free and open Internet.

Project Galileo: Since 2014, we've equipped more than 2,400 journalism and civil society organizations in 111 countries with powerful tools to defend themselves against attacks that would otherwise censor their work, technology already used by Cloudflare’s enterprise customers-at no cost.

Athenian Project: In 2017, we created the Athenian Project to ensure that state and local governments have the highest level of protection and reliability for free, so that their constituents have access to election information and voter registration. Since the project, we've provided services to more than 425 local government election websites in 33 states.

1.1.1.1: We released 1.1.1.1 to help fix the foundation of the Internet by building a faster, more secure and privacy-centric public DNS resolver. This is available publicly for everyone to use – it is the first consumer-focused service Cloudflare has ever released. Here's the deal – we don't store client IP addresses never, ever. We will continue to abide by our privacy commitment and ensure that no user data is sold to advertisers or used to target consumers.

Please note that applicants who progress to the offer stage of the interview process may be asked to attend an in‑person interview within one of the Cloudflare Offices or Cloudflare Hubs. More details about this will be available at that stage of the interview process.

This position may require access to information protected under U.S. export control laws, including the U.S. Export Administration Regulations. Please note that any offer of employment may be conditioned on your authorization to receive software or technology controlled under these U.S. export laws without sponsorship for an export license.

Cloudflare is proud to be an equal opportunity employer. We are committed to providing equal employment opportunity for all people and place great value in both diversity and inclusiveness. All qualified applicants will be considered for employment without regard to their, or any other person's, perceived or actual race, color, religion, sex, gender, gender identity, gender expression, sexual orientation, national origin, ancestry, citizenship, age, physical or mental disability, medical condition, family care status, or any other basis protected by law. We are an AA/Veterans/Disabled Employer. Cloudflare provides reasonable accommodations to qualified individuals with disabilities. Please tell us if you require a reasonable accommodation to apply for a job. Examples of reasonable accommodations include, but are not limited to, changing the application process, providing documents in an alternate format, using a sign language interpreter, or using specialized equipment. If you require a reasonable accommodation to apply for a job, please contact us via e-mail or via mail at 101 Townsend St. San Francisco, CA 94107.