Browser Security Engineer: Chromium Security & Unlimited PTO

Doist; San Francisco (CA); On-site; USD 150,000 - 210,000; Full time

Benefits offered by this job

Industry-competitive salary

Equity

Medical + dental coverage

Dependent coverage

Relocation assistance

Unlimited PTO

401k + company match

Job summary

Kernel is a fast, open source browser infrastructure for AI agents, handling autoscaling and secure isolation. We’re building a Chromium-based runtime used by developers to run thousands of concurrent web interactions with reproducible builds.

We’re seeking a Browser Security Engineer to harden the runtime, focusing on sandboxing, networking, and microVM isolation. You’ll work with low-level tools to debug, patch, and optimize Chromium within Kernel’s infrastructure and collaborate with a senior

Qualifications

• Deep familiarity with Chromium internals or browser sandboxes.
• Experience with Linux kernel, microVMs, or container isolation.
• Strong debugging skills with low-level tools (strace, gdb, perf).

Responsibilities

• Debug, patch, and optimize Chromium builds in Kernel’s microVM environments.
• Implement and maintain network isolation, proxy routing, and IP handling for browsers.
• Collaborate with infra engineers on unikernel-based isolation and kernel security policies.
• Build internal tooling for binary analysis, crash triage, and vulnerability monitoring.
• Support secure supply chain and reproducible builds for browser images.

Skills

Chromium internals

Browser sandboxes

Renderer/network stacks

Linux kernel

microVMs

low-level debugging

networking basics

Tools

strace

gdb

perf

Job description

Kernel is a fast, open source browser infrastructure for AI agents, handling autoscaling and secure isolation. We’re building a Chromium-based runtime used by developers to run thousands of concurrent web interactions with reproducible builds.

We’re seeking a Browser Security Engineer to harden the runtime, focusing on sandboxing, networking, and microVM isolation. You’ll work with low-level tools to debug, patch, and optimize Chromium within Kernel’s infrastructure and collaborate with a senior