Senior Software Engineer, Browser Automation
Horizon3 · Remote · US, Remote ·
COMPENSATION
€•• – ••k
Listed on the employer's job board (Ashby)
- Senior level role
- Fully remote option
- TypeScript + Node.js
- Playwright & Stagehand
- $199k-$235k base
You will own the crawling and navigation layer of an autonomous black-box penetration tester. Your work enables the system to reliably log in, navigate SPAs, and map attack surfaces in production environments without causing harm or generating false positives.
The team combines former special operations cyber operators and engineers to solve security challenges like alert fatigue and blind spots. You will collaborate with attack-team engineers to shape the application map that powers the rest of the pipeline.
What you'll do
- Harden the browser automation engine that discovers and navigates target applications
- Advance the crawler using Playwright and Stagehand frameworks
- Handle SPA routing, hydration timing, and authenticated sessions reliably
- Extend agentic login capabilities for complex auth flows and MFA/TOTP
- Improve crawl coverage, determinism, and throughput via queueing and dedupe
- Apply LLM models surgically only when deterministic approaches fail
- Collaborate with attack engineers to define the graph-backed application map
What you'll need
- Deep hands-on experience with Playwright, Puppeteer, or Selenium
- Strong TypeScript and Node.js skills for headless-browser stacks
- Knowledge of Chromium internals and Chrome DevTools Protocol
- Proven track record taming flaky, stateful, JavaScript-heavy apps
- Experience with distributed systems concepts like backpressure and retries
- Bias toward determinism and debuggability in automation logic
- Comfort taking ownership of critical subsystems for unattended scale
Nice to have
- Experience with agentic browser frameworks or LLM-in-the-loop automation
- Background in web application security or offensive tooling
- Familiarity with graph data models such as Neo4j
- Experience with large-scale crawling and client-side JS analysis
- Contributions to the internals of tools like Playwright or Puppeteer
- Success outmaneuvering WAFs and anti-bot defenses in production
Stack
- TypeScript
- Node.js
- Playwright
- Puppeteer
- Selenium
- Stagehand
- Chromium
- Neo4j
How you'll work
- Remote and hybrid work models available
- Some roles may require presence in Chicago office
- Flexible vacation policy offered
What you get
- Base salary range $199,000 to $235,000 annually
- Equity package in the form of stock options
- Health, vision, and dental insurance for family
- Generous parental leave
- Inclusive culture valuing diversity and equity