Staff Software Engineer - Linux Kernel

About the role

Fastly's Kernel and Host Networking team builds and ships the Linux kernel that runs on every server in its global edge network. As a Staff engineer you own technical problems end to end, from a crash signature or a new NIC on the bench, through root cause and design, to a change that is upstreamed and running on thousands of servers. The work spans networking, XDP and eBPF, memory, performance and hardware enablement, and covers layers. Formal CS education is not required; demonstrable experience is what matters.

Key responsibilities

• Set technical direction for kernel projects, own them end to end and mentor engineers on the team.
• Bring new servers, CPUs and NICs from first boot to full fleet: drivers, IRQ affinity, RSS and queue layout on high core-count hosts.
• Improve datapath and transport performance with XDP, eBPF and protocol work based on IETF specifications.
• Debug cross-layer problems with application teams, such as MTU behavior, cgroup memory accounting and packet filtering.
• Develop and maintain kernel changes and Fastly kernel modules on the long-term kernel line, reducing the private delta by upstreaming.
• Ensure state pushed from control planes to eBPF and XDP programs is applied, verified and safe to roll back.
• Own kernel health in production: triage crashes, WARNs and regressions, find root cause and ship fixes.
• Own and improve the kernel release process: CI, bake, canary, staged rollout and rollback, plus crash metrics and drift detection.
• Join the on-call rotation, lead the kernel side of incidents and drive follow-up actions to closure.

Required profile

• 7+ years of related engineering experience, including substantial production C, with 3 of those years leading technical projects.
• Production Linux kernel development, including debugging use-after-free, refcount and leak bugs with KASAN, kdump, ftrace, perf or bpftrace.
• Working knowledge of the scheduler and memory management (EEVDF, memcg).
• Experience managing a kernel patch stack and working with upstream communities.
• Solid understanding of the Linux network stack (TCP/IP, sk_buff lifecycle, qdiscs, NIC drivers) and XDP or eBPF, with deep expertise in at least one of these.
• Operational discipline: staged rollouts, canaries, kill switches, observability, postmortems and closing action items.
• Understanding of distributed systems: control plane and datapath consistency, partial failure and safe config rollout at fleet scale.
• Ability to design broadly scoped work and drive it across teams.

Nice to have: upstream kernel contributions or subsystem maintainership; deep knowledge of QUIC, TCP, ECN and L4S, MASQUE; hardware enablement on AMD EPYC or Intel platforms and NIC drivers such as mlx5, ice or i40e; load balancing or traffic steering systems; CDN or large edge network environments; container networking (network namespaces, veth, cgroups, eBPF-based CNI datapaths).

What we offer

• Estimated salary range of $211,370 to $253,644 in the US, with starting salary depending on experience, skills and location.
• Medical, dental and vision insurance, family planning and mental health support, Employee Assistance Program, and life, disability and accident insurance.
• Flexible vacation policy and up to 18 days of accrued paid sick leave.
• 401(k) with company match and an Employee Stock Purchase Program.
• 11 paid local holidays and 12 paid company wellness days in 2026.

The position is open to remote and hybrid work in the US, with offices in New York, San Francisco and Denver, and may require travel. Availability during core business hours and participation in an on-call rotation is required.