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Stay22 is a Montreal-based platform that helps creators and digital platforms monetize their traffic through embedded widgets and affiliate technology. The company processes over $1 billion in annual transactions and serves 6,500+ creators and platforms across travel, retail, lifestyle, publishing, events, and transport.
As a Senior Fullstack Developer on the Phantom team, you will own the embedded widget and affiliate platform, focusing on browser script performance and reliability. You will design and optimize client-side scripts that run across diverse third-party websites, ensuring fast load times and seamless execution under real-world constraints.
Key responsibilities include:
- Continuously optimize browser script load time and execution efficiency through minification, caching, lazy loading, and other performance techniques
- Create robust mechanisms for injecting content and widgets into arbitrary websites, including DOM manipulation and handling dynamic page layouts
- Architect and execute A/B/n experimental setups with analytics teams, using data metrics to guide product decisions
- Build and maintain Node.js and Python-based scrapers to collect data from partner websites and APIs; design fallback data sources for resilience
- Implement privacy-conscious session tracking and browser fingerprinting methods
- Troubleshoot and adapt runtime logic for real-world usage, including handling unexpected page structures and third-party script conflicts
- Own the entire embedded product stack (scripts, SDKs, APIs) and collaborate with other teams on smooth integration of updates and features
- Apply Express.js middleware expertise and core security principles to server-side code
The company offers a vibrant Montreal HQ in Little Italy with gym access, cafeteria allowance, rooftop terrace with seasonal sports facilities, comprehensive health and dental coverage, RRSP matching, fully paid transit passes, flexible schedules, work-from-anywhere opportunities, and regular team events and retreats.
Requirements:
- Deep hands-on experience with vanilla JavaScript and ES6+ or TypeScript without relying on frameworks for core logic (no React/Vue/etc. for system logic)
- Strong knowledge of browser event loop, DOM API, CSSOM, rendering pipeline, and optimization for First Contentful Paint (FCP) and Largest Contentful Paint (LCP)
- Proficiency with Node.js for building APIs and web scrapers; Python-based scraping experience is a plus
- Familiarity with HTTP, REST/JSON, and proxies
- Understanding of browser fingerprinting methods and privacy considerations (cookie/session management, CORS, GDPR)
- Public GitHub contributions or open-source involvement strongly preferred
- Bachelor's or Master's in Computer Science or equivalent professional software development experience is a plus
