Spectrum Systems Engineer: High-Scale L4 Proxy

Cloudflare; Austin (TX); On-site; USD 150,000 - 210,000; Full time

Job summary

Cloudflare is seeking a Systems Engineer for the Spectrum team within the Packet Processing group. You will own and evolve a high-scale L4 proxy, collaborating across teams to deliver reliable, production-grade networking software that powers a significant portion of the internet.

The role emphasizes Go development, systems engineering, and deep understanding of TCP/UDP networking. Locations include Austin, TX and London, with a focus on performance and reliability at scale.

Qualifications

• Experience building large-scale distributed systems.
• Strong programming experience in Go; familiarity with Rust is a plus.
• Solid understanding of L3/L4 networking: TCP/UDP, IP, NAT, and packet flows.
• Experience with Linux networking primitives - sockets, eBPF, namespaces, nftables, tc.
• Experience designing RESTful APIs and backend systems.
• Comfort with production operations, on-call and incident response.

Responsibilities

• Spectrum edge dataplane development in Go: connection acceptance, forwarding, TLS termination, and protocol support.
• Spectrum control plane development in Go: configuration APIs and provisioning.
• Integrations with Unimog, Magic Transit, and Argo Smart Routing.
• Maintaining performance, observability, and reliability at scale.
• Roadmap evolution for Spectrum as the L4 counterpart to the HTTP proxy stack.

Skills

Go

Rust

Networking

eBPF

APIs

Tools

Unimog

Magic Transit

Cloudflare WAN

Spectrum

Job description

Cloudflare is seeking a Systems Engineer for the Spectrum team within the Packet Processing group. You will own and evolve a high-scale L4 proxy, collaborating across teams to deliver reliable, production-grade networking software that powers a significant portion of the internet.

The role emphasizes Go development, systems engineering, and deep understanding of TCP/UDP networking. Locations include Austin, TX and London, with a focus on performance and reliability at scale.