Systems Reliability Engineer - Core

Cloudflare • San Francisco, CA

3d

About The Position

Cloudflare is seeking a Systems Engineer to architect, scale, and operate the distributed infrastructure powering its global server fleets. The role drives automation and reliability work to keep systems fast and resilient at scale, and builds tools that help engineers safely and efficiently deploy and operate Cloudflare services. The Core platform teams provide a reliable, flexible private cloud that Cloudflare product teams use to build Cloudflare itself. Platforms and tools include Kubernetes; Postgres, PgBouncer, and Stolon; Kafka; Zookeeper; Ceph and Rook; developer tools and CI/CD systems; Vault; Consul; Etcd; Temporal; and artificial intelligence and LLM technologies.

The engineer will architect and maintain robust distributed systems, optimize system performance, develop infrastructure automation, monitor reliability, and collaborate with Security, Network Engineering, and Product teams. Hiring locations are Lisbon, Portugal, and London, UK. Applicants progressing to the offer stage may be asked to attend an in-person interview at a Cloudflare office or hub. The position may require access to information subject to U.S. export control laws; an offer may be conditioned on authorization to receive controlled software or technology without export-license sponsorship.

Requirements

• Professional experience building and managing large-scale distributed systems or Linux production environments.
• Proficiency in at least one systems programming or scripting language, such as Go, Rust, C/C++, or Python, with a record of writing clean, maintainable code.
• Deep understanding of Linux/Unix operating system internals, such as storage subsystems and memory management, and core networking protocols including TCP/IP, DNS, and BGP.
• Experience with configuration management and infrastructure-as-code tools such as Ansible, Terraform, or SaltStack.
• Strong analytical and troubleshooting skills, with a methodical approach to diagnosing complex system-level failures.

Nice To Haves

• Experience managing containerized 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 systems engineering community.
• Experience with Cloudflare's existing tooling, such as Kafka and Temporal.
• Experience harnessing AI to drive robust solutions.

Responsibilities

• Architect, deploy, and maintain distributed systems designed for high availability, low latency, and horizontal scalability.
• Analyze system bottlenecks, optimize kernel and network stacks, and fine-tune resource utilization across global server fleets.
• Build and maintain internal tools and automation frameworks for infrastructure deployment, configuration management, and monitoring.
• Participate in architecture reviews, capacity planning, and proactive system health monitoring to support uptime and resilience.
• Collaborate with Security, Network Engineering, and Product teams to integrate infrastructure solutions across the technology stack.
• Build tools and platform capabilities that help product teams deploy and operate services efficiently and safely.

What This Job Offers

• Job Type: Full-time
• Education Level: No Education Listed