Systems Engineer, Spectrum

Requirements

• Experience building and shipping large-scale, reliable, highly distributed systems
• Strong programming experience in Go; familiarity with or willingness to work in Rust is a plus
• Solid understanding of L3 and L4 networking: TCP, UDP, IP, connection state, NAT, anycast, and packet flows
• Experience with Linux networking primitives — sockets, eBPF, network namespaces, netfilter/nftables, tc
• Experience designing and integrating RESTful APIs and backend systems
• Comfort with operating what you build in production — on-call rotations, incident response, and root-cause analysis
• Ability to reason about existing systems at scale: reading unfamiliar code, understanding hidden dependencies, and safely evolving software that has been in production for years
• Excellent debugging and optimization skills, particularly around performance and connection lifecycle issues
• Focus on clarity in written and verbal communication; ability to work across teams to land shared solutions

Nice to Haves

• Experience with TLS termination, PROXY protocol, or L4/L7 proxies (Envoy, HAProxy, nginx stream, etc.)
• Experience with ClickHouse, Kafka, or large-scale connection/flow analytics pipelines
• Experience with globally-distributed KV or config-push systems
• Prior work on DDoS mitigation, anycast routing, L4 load balancing, or high-throughput edge network daemons
• Contributions to open-source networking or proxy projects

What You'll Be Doing

• The Spectrum edge dataplane (Go): TCP/UDP connection acceptance and forwarding, TLS termination, PROXY protocol, connection accounting, and eBPF integrations
• The Spectrum control plane (Go): application configuration APIs, provisioning, and the systems that push config globally to every edge machine
• Cross-dataplane integrations: how Spectrum fits together with Unimog for L4 load balancing, with Magic Transit for IP transit, with Argo Smart Routing for accelerated origin paths, etc
• Operational excellence: analytics pipelines, observability, on-call, incident response, and paying down technical debt in a product with a long production history
• Roadmap evolution: help shape where Spectrum goes next as the L4 counterpart to our HTTP proxy stack

Perks and Benefits

• Opportunity to work on a critical, high-scale L4 proxy shaping the next generation of Cloudflare's non-HTTP traffic platform
• Collaboration with various teams across Cloudflare, solving problems spanning the entire stack