Senior Software Engineer - Browser

Senior Software Engineer (EMEA) Born out of the heart of the Basque Country in Bilbao, ZenRows is one of the fastest-growing startups in Europe! We work 100% remotely and believe in hiring the best people, no matter where you are in the world!    Founded in 2021, our mission is to transform the future of data workflows by enabling seamless, large-scale data extraction from the web. With our powerful tools, businesses can automate data collection at scale while leveraging the most advanced anti-bot bypass system on the market. Thousands of companies worldwide—across industries like e-commerce, real estate, finance, and AI—rely on ZenRows to streamline their data pipelines, fueling automation, analytics, and AI-driven insights   As we continue our rapid expansion, we are now looking for a Senior Software Engineer to join us on a permanent basis and make an instant impact.  The Role:  We’re looking for a Senior Software Engineer to join our Stealth & Reverse Engineering team—the elite force responsible for making our headless browsers and traffic completely undetectable by modern anti-bot systems. You will own and evolve our custom fork of Chromium, continuously identifying and patching all behavioral and fingerprinting vectors that reveal automation. You'll go deep into browser internals, reverse engineer anti-bot defenses, and create a fully cloaked browsing experience across real-world targets. You’ll also build internal tools that detect, analyze, and resolve JavaScript-based bot challenges (like fingerprinting, integrity checks, proof-of-work, and obfuscation traps), and help automate evasions across our infrastructure. This is a deeply technical, adversarial, and high-leverage role at the heart of what makes our scraping infrastructure world-class. We’re a remote-first company with a fast-paced, high-impact culture. In this role, you’ll work closely with our CEO, Aurken, and our Director of Engineering. And as a business with two technical founders who have strong engineering backgrounds—you must be comfortable engaging in technical discussions while balancing business needs. Key Responsibilities: 🧬 Browser Fingerprinting & Chromium Patching Own and evolve our Chromium fork, maintaining full control over browser behavior and instrumentation. Patch and neutralize browser fingerprinting surfaces: canvas, audio, WebGL, screen, navigator, user agent, and more. Harden the browser against integrity checks (function.toString, error stack traces, memory layout, etc.). Ensure parity with real users under advanced detection tools like FingerprintJS, Datadome, PerimeterX, and others. 🔬 Reverse Engineering & Challenge Automation Analyze real-world JavaScript challenges and traps designed to detect bots. Reverse engineer obfuscated payloads and evasive scripts using tools like Chrome DevTools, Frida, Wireshark, mitmproxy, etc. Build internal tooling to automatically detect, triage, and solve bot challenges, integrati...