Senior Software Engineer - JavaScript / TypeScript

Overview

Job Description

Responsibilities

• - 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

Required Skills

• - 3-5 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 Vite, Webpack, Rollup, Esbuild, including code obfuscation and minification
• - Experience with modern testing frameworks such as Vitest, 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