Senior Software Engineer, Browser Automation

Horizon3.ai
United States
Workplace: RemoteFull timeUSD 169,000 - 208,000 annuallyFunction: Software EngineeringSkills: ["Ownership","Collaboration","Problem-solving","Communication","Prioritization"]

Join Horizon3.ai to build and scale the browser automation and crawling engine for an autonomous, production-safe web application pentest platform. You’ll advance Playwright-based crawling, tackle complex SPA and auth scenarios, improve coverage and throughput, and blend deterministic automation with selective LLM-driven navigation in a security-focused, distributed system.

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FursaFursa
Horizon3.ai
Horizon3.ai
2 months ago

Senior Software Engineer, Browser Automation

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Source: Company careers pageValidated by: Fursa AI
Last checked: 16 hours agoStatus: Live

Job Summary

Join Horizon3.ai to build and scale the browser automation and crawling engine for an autonomous, production-safe web application pentest platform. You’ll advance Playwright-based crawling, tackle complex SPA and auth scenarios, improve coverage and throughput, and blend deterministic automation with selective LLM-driven navigation in a security-focused, distributed system.
Location: United States
Workplace: Remote
Employment Type: Full time
Job Function: Software Engineering

Key Responsibilities

  • •Grow and harden our browser automation and crawling engine—the layer that discovers, navigates, and interacts with target applications before and during an autonomous pentest.
  • •Advance our browser-driven crawler using Playwright and Stagehand.
  • •Tackle modern web app realities: SPA routing/hydration timing, authenticated sessions, multi-step flows, file uploads, WebSocket/Socket.IO traffic, infinite scroll, and crawler traps.
  • •Extend our agentic login and authentication capabilities, including complex auth flows, MFA/TOTP, and credentialed access reliable enough to run unattended against customer environments.
  • •Improve crawl coverage, determinism, and throughput through endpoint and parameter discovery, dedupe, queueing, and state management while keeping production-safety in mind.

Pay and Benefits

Salary: USD 169,000 - 208,000 annually
Equity and Bonus:Equity
Perks:Health InsuranceVisionDentalParental LeaveEquity

Key Requirements

  • •Experience building production software with deep hands-on browser automation (Playwright, Puppeteer, or Selenium) against real, non-trivial web applications.
  • •Strong TypeScript / Node.js skills and comfort with the headless-browser stack, including Chromium internals, Chrome DevTools Protocol, network interception, the DOM, and JS execution contexts.
  • •Track record of taming flaky, stateful, JavaScript-heavy apps; you’ve fought SPA timing, authentication, and anti-automation defenses.
  • •Solid instincts for distributed/concurrent systems: queues, backpressure, retries, idempotency, and running many browser sessions reliably at scale.
  • •Bias toward determinism and debuggability; judgment to reach for an LLM only when a deterministic approach genuinely can’t do the job.
Experience:CybersecuritySaaS
Skills:OwnershipCollaborationProblem-solvingCommunicationPrioritization
Languages:English
Tech Stack:PlaywrightStagehandTypeScriptNode.jsChromiumChrome DevTools ProtocolSocket.IOLLMsPuppeteerSelenium

Company Brief

Horizon3.ai
Builds NodeZero®, an autonomous penetration-testing platform that continuously finds, prioritizes, and verifies exploitable vulnerabilities across on-premises, cloud, and hybrid environments to help organizations reduce security risk.
Industry: Cybersecurity
Company Size: Large (251 to 1,000 employees)
Growth: Scaleup
Funding: Series D
Headquarters: San Francisco, United States
Founded: 2019
Glassdoor
Glassdoor: 4.9
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