JavaScript / Typescript Engineer, Fingerprint

• Can you walk through the JavaScript event loop in your sleep
• Do you understand the browser rendering pipeline better than most devs understand their own code
• Have you ever built your own JavaScript framework just for fun
• Love open source
• Then you might be exactly who we’re looking for
• If you want to push the boundaries of what’s possible in the browser, apply today
• 6-10 years of JavaScript and TypeScript experience, especially in browser environments
• Deep understanding of browser APIs, DOM behavior, timing attacks, and anti-debugging techniques
• Experience building libraries or SDKs, especially for production or developer-facing use cases
• Strong frontend experience (~80%), with backend familiarity (~20%)
• Proficiency with build tools like Webpack, Rollup, Esbuild, including code obfuscation and minification
• Experience with modern testing frameworks such as Jasmine, Jest, or similar
• Familiarity with security principles, privacy best practices, and adversarial engineering
• Comfortable working in fast-paced environments without rigid specifications
• Strong sense of ownership and autonomy; you enjoy working independently and solving hard technical problems
• Clear written and verbal communication skills in English

Desirable

• This is backend-level engineering that happens to run in the most hostile, performance-constrained environment there is: the browser
• We’re hiring a TypeScript/JavaScript Engineer to own our browser-side JavaScript agent, CDN integrations, and performance-critical SDKs used by millions every day
• You’ll be crafting tamper-resistant, lightning-fast code that survives in the wild—pushed to its limits by scale, security threats, and the quirks of every browser under the sun
• Build and maintain our browser-side TypeScript/JavaScript agent used for device identification, bot detection, and risk assessment
• Engineer for stealth, resilience, and performance—minimizing footprint, resisting detection, and maintaining compatibility across browsers
• Optimize for both code size and execution speed in complex, adversarial environments
• Stay ahead of browser changes, plugin behaviors, and fingerprinting techniques
• Collaborate with backend, security, and data science teams to align signal capture with detection logic
• Write comprehensive tests and contribute to CI pipelines that ensure functionality across a wide range of platforms and devices
• Contribute to a widely-used open-source project with 24K+ GitHub stars and 25B+ monthly usages