Browser Security Engineer

Kernel•San Francisco, CA

About The Position

We’re building the developer platform that lets AI agents use applications, starting with browsers. Our edge is an infrastructure platform that’s extensible, observable, and built for scale from day one. Our platform handles the hard stuff: spinning up browsers quickly and efficiently at scale, providing great observability into their activity, and enabling both humans and AI agents to interact with them. If you’re interested in building critical infrastructure for the next generation of AI applications, we’d love to chat. 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.

Requirements

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).

Nice To Haves

Background in security engineering or browser hardening a plus.

Responsibilities

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.