Senior Software Engineer, Browser Automation

Horizon3.ai

Senior Software Engineer developing browser automation for cybersecurity company's penetration testing applications. Collaborating with teams to improve automated security assessments and tackling complex web app challenges.

Posted 6/23/2026full-timeRemote • 🇺🇸 United StatesSenior💰 $169,000 - $208,000 per yearWebsite

Tech Stack

Tools & technologies

JavaScriptNode.jsPuppeteerSeleniumTypeScript

About the role

Key responsibilities & impact

Help us grow and harden our browser automation and crawling engine
Advance our browser-driven crawler using Playwright and Stagehand
Tackle modern web app challenges: SPA routing, multi-step flows, etc.
Extend agentic login and authentication capabilities
Improve crawl coverage, determinism, and throughput
Collaborate with attack-team engineers to shape application maps

Requirements

What you’ll need

Experience building production software, with deep hands-on experience in browser automation (Playwright, Puppeteer, or Selenium)
Strong TypeScript / Node.js skills
A track record of dealing with flaky, stateful, JavaScript-heavy apps
Solid instincts for distributed/concurrent systems
A bias toward determinism and debuggability
Ownership mentality

Benefits

Comp & perks

Health, vision & dental insurance for you and your family
Flexible vacation policy
Generous parental leave
Growth opportunities
Innovative culture

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills & Tools

browser automationPlaywrightPuppeteerSeleniumTypeScriptNode.jsdistributed systemsconcurrent systemsdebuggabilitydeterminism

Soft Skills

ownership mentality