Systems Reliability Engineer - Core

Hiring Locations: Lisbon, Portugal, London, UK

About the Role

We are looking for a Systems Engineer to architect, scale, and operate the distributed infrastructure that powers our global server fleets. You will drive automation and reliability work that keeps our systems fast and resilient at scale.

Responsibilities

Cloudflare is a system spanning the globe, on a mission to make the internet better, safer, and more powerful everyday. With this goal in mind, our product teams are responsible for deployed thousands of deployments at an ever increasing rate.

As an engineer on one of our Core platform teams, you'll be building the tools to help engineers deploy and operate the services that make Cloudflare work. Our mission is to provide a reliable, yet flexible, platform to help product teams release new software efficiently and safely. You’ll be building the private cloud that Cloudflare developers leverage to build Cloudflare itself. Core platforms we operate at Cloudflare include:

Kubernetes

Postgres, PgBouncer, and Stolon

Kafka

Zookeeper

Ceph & Rook

Developer tools, CI, and CD systems

Vault

Consul

Etcd

Temporal

Artificial Intelligence & LLMs

You will

Architect, deploy, and maintain robust distributed systems, focusing on high availability, low latency, and horizontal scalability.

Optimise Performance: Analyse system bottlenecks, optimise kernel and network stacks, and fine-tune resource utilisation across global server fleets.

Drive Automation: Build and maintain internal tools and automation frameworks to streamline infrastructure deployment, configuration management, and monitoring.

Ensure Reliability: Participate in architecture reviews, capacity planning, and proactive system health monitoring to guarantee maximum uptime and resilience.

Collaborate Cross-Functionally: Partner closely with Security, Network Engineering, and Product teams to integrate infrastructure solutions smoothly across the entire stack.

Desirable Skills, Knowledge, and Experience

Demonstrable professional experience building and managing large-scale distributed systems or Linux production environments.

Proficiency in at least one systems programming or scripting language (e.g., Go, Rust, C/C++, Python) with a track record of writing clean, maintainable code.

Deep understanding of Linux/Unix operating system internals (e.g., storage subsystems, memory management) and core networking protocols (TCP/IP, DNS, BGP).

Experience with configuration management and infrastructure-as-code tools (e.g., Ansible, Terraform, SaltStack).

Strong analytical and troubleshooting skills, with a methodical approach to diagnosing complex system-level failures.

Bonus Points

Experience managing containerised workloads at scale using Kubernetes, Docker, or similar orchestration platforms.

Familiarity with CI/CD pipelines and automated testing strategies for infrastructure.

Contributions to open-source systems software projects or active participation in the broader systems engineering community.

Experience with any of our existing tooling, such as Kafka and Temporal

Good experience of harnessing AI to drive robust solutions

What Makes Cloudflare Special?

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.