About the role

What will you do at Kernel?

About Kernel

Kernel is crazy fast, open source browser infrastructure for AI agents. We handle autoscaling, observability, and the messy details of web interaction, so developers can focus on what their agents do instead of how they do it.

Teams at Cash App, Framer, and 7000+ others use Kernel for deep research, QA automation, and real-time web analysis. We've raised $22M from Accel, YC, and Vercel.

If you're interested in building critical infrastructure for agents on the web, we'd love to chat.

About the role

We’re hiring a Browser Security Engineer to harden and extend our Chromium-based browser runtime. You’ll work at the intersection of sandboxing, networking, and virtualization — ensuring our browsers run securely and efficiently across thousands of concurrent users.

What you’ll do

Debug, patch, and optimize Chromium builds running inside Kernel’s microVM environments.

Implement and maintain network isolation, proxy routing, and IP handling for browsers.

Collaborate with infra engineers on unikernel-based isolation, process scheduling, and kernel security policies.

Build internal tooling for binary analysis, crash triage, and vulnerability monitoring.

Support the team in maintaining secure supply chain and reproducible builds for our browser images.

What we’re looking for

Deep familiarity with Chromium internals, browser sandboxes, or renderer/network stacks.

Experience with Linux kernel, microVMs (Firecracker, Cloud-Hypervisor, Kata, gVisor, etc.), or container isolation.

Strong debugging skills with strace, gdb, perf, or similar low-level tools.

Knowledge of networking fundamentals (DNS, TCP/IP, NAT, proxies, TLS).

Background in security engineering or browser hardening a plus.

What you can expect as a Kernel

Industry-competitive salary

Above market equity

Premium medical + dental coverage + dependent coverage

Small, trusting team of senior + staff engineers

Default async with minimal bureaucracy

Daily lunches on us

Unlimited PTO

401k + company match

Relocation assistance

Hiring process

We have a simple process focused on real world collaboration and jointly getting to know each other:

30 minute intro calls with one of Kernel’s co-founders

45-minute technical interview (virtual)

Half-day on-site (in-person) working with our team on relevant technical challenges.

Offer!

Which skills does this role require?

Chromium internalsBrowser sandboxingLinux kernelMicroVMsContainer isolationStraceGdbPerfNetworking fundamentalsDNSTCP/IPNATProxiesTLSSecurity engineeringBrowser hardeningChromiumBrowser SecurityMicroVMFirecrackerCloud-HypervisorKatagVisorLinux KernelNetworkingBinary AnalysisVulnerability MonitoringInfrastructureSandboxingRendererNetwork StacksContainer IsolationSecurity EngineeringBrowser HardeningUnikernelProcess SchedulingSupply Chain SecurityReproducible Builds

Make your next move

Build a shortlist and prepare

Identify the requirements you can demonstrate, then choose examples from your work to discuss with the hiring team.

Build a focused shortlist before you applyCompare role requirements with your experience and give each application a clear reason.
Practice explaining your experience in an interviewRehearse your answers before meeting the hiring team.

Review the responsibilities and requirements before adding an opening to your shortlist.