Senior Software Engineer (Frontend, Growth)

Responsibilities

• Own the architecture and technical direction of WHOOP's web experiences, including our Next.js-based join flow, Cloudflare Workers edge infrastructure, and Stripe-powered checkout
• Lead cross-functional projects end-to-end from brainstorm and technical planning through implementation, QA, rollout, and post-launch analysis, partnering closely with Product, Design, and Analytics
• Design and execute experiments (A/B tests) with rigor, ensuring proper instrumentation, measurement, and iteration based on impact to North Star metrics
• Drive frontend performance, accessibility, and reliability across devices and browsers, establishing standards and monitoring that the team can build on
• Write clean, well-tested, production-quality code in TypeScript/React/Next.js and integrate deeply with backend services, payment systems (Stripe), and ecommerce platforms (CommerceTools)
• Author and review technical plans, identify architectural tradeoffs, and make sound judgment calls that balance speed with long-term maintainability
• Mentor and develop other engineers through code review, pairing, and technical guidance, raising the bar for quality and velocity across the web surface
• Participate in on-call rotations and incident response; lead postmortems and drive improvements that prevent recurrence
• Contribute to Growth's engineering culture through documentation, process improvements, and knowledge sharing

Qualifications

• 5+ years of professional experience in frontend software engineering, with deep expertise in TypeScript, React, and modern web frameworks (Next.js strongly preferred)
• Track record of owning and delivering complex, cross-functional web projects from technical design through production rollout
• Strong understanding of web performance optimization, edge computing (e.g., Cloudflare Workers), and responsive design at scale
• Experience integrating frontend applications with payment systems (Stripe preferred), RESTful APIs, and third-party platforms
• Demonstrated ability to design and run meaningful A/B tests and make data-informed decisions in a growth or product engineering context
• Experience with observability and monitoring tools (e.g., Datadog, Sentry, Amplitude) to proactively identify and resolve production issues
• Proven ability to mentor engineers, lead technical discussions, and influence engineering practices across a team
• Excellent written and verbal communication skills; comfortable operating in an async-first, cross-functional environment

Bonus: Experience with ecommerce platforms (CommerceTools), feature flag / experimentation infrastructure, or subscription/membership business models