Systems Engineer, Spectrum

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.

As a member of Spectrum in the Packet Processing team, we're looking for a Systems Engineer who wants to take shared ownership of a critical, high-scale L4 proxy and help evolve it into the next generation of Cloudflare's non-HTTP traffic platform.

Responsibilities:

• 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

Desirable Skills, Knowledge, and Experience:

• 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

Bonus Points:

• 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