Full Stack Product Engineer

🐘 About Liftoff Our Mission: Making the world a better, healthier place by gamifying fitness Liftoff is the Duolingo of fitness, empowering anyone to start and stay at the gym, so that they develop healthier and powerful habits. We're a mission-driven team of young founders who move fast, own the details, and do the work. We're fully bootstrapped and built this company from zero to $8M+ in ARR in under two years, and have done so profitably. If you're excited to help build a world-class team, shape a high-performance culture, and make a real impact alongside people who are deeply committed, we'd love to meet you. 🌟 About the Team You'll join the Product team and work closely with the Head of Product, collaborating with Engineering, Design, and Growth Our product is the engine behind everything: retention, monetization, and ultimately revenue. This role is for someone who wants end-to-end ownership over backend reliability and experiment velocity, and loves shipping. 🎯 About the Role We're hiring a Full-Stack Engineer to own backend maintenance and drive experiment implementation across the org. Your core focus areas: Backend health, performance, and scalability Experiment infrastructure and instrumentation API reliability and internal tooling Cross-functional shipping with Product and Growth This is a high-ownership role. You can be: A backend-first engineer who's exceptional at systems design, reliability, and data infrastructure, or A full-stack generalist who can move between backend, experiment wiring, and front-end changes fluidly Either way, you own outcomes. You'll work with our existing team/resources and ship directly. ✅ What Success Looks Like Backend systems that are fast, reliable, and easy for the team to build on A high-velocity experiment pipeline: clean instrumentation → fast implementation → reliable measurement → iteration Shipped infrastructure improvements that compound (reusable experiment patterns, better event tracking, faster deploys, fewer incidents) Strong operating cadence with crisp communication on what's shipping, why, and what it did 🛠️ What You'll Do Own backend reliability and performance Maintain and improve our Supabase/Postgres backend, serverless infra, and APIs Resolve technical debt, optimize queries, manage migrations, and ensure uptime Ship experiments and instrumentation Partner with Product/Growth to implement A/B tests and feature flags via Statsig Ensure every experiment has clean event tracking and reliable data Build reusable patterns that reduce experiment cycle time Use data to drive decisions Instrument events properly so the team can trust experiment results Spot measurement issues (leaky cohorts, misconfigured flags, underpowered tests) before they corrupt decisions Collaborate cross-functionally Work with Product and Growth to align experiment implementation with the roadmap Work with Design to ship front-end changes in React Native / Expo when experiments require it Contribute to prioritization by bringing technical feasibility and effort estimates 🔍 You'll Likely Succeed If You Have We don’t expect you to check every box. We care most about ownership, judgment, and shipping. Professional backend/full-stack experience in a production environment Strong Node.js and relational database experience (Postgres strongly preferred) Hands-on experience with experimentation infrastructure: feature flags, A/B tests, event tracking Demonstrated ability to ship autonomously in a fast-paced, low-structure environment Clear written communication; can document decisions, write specs, and share learnings 🌱 Bonus Attributes Experience with our specific stack: Supabase, Vercel, tRPC, Statsig, RevenueCat Familiarity with React Native / Expo (enough to make front-end changes, not to be the primary mobile dev) Background in subscription/consumer apps - understanding of trials, paywalls, LTV, ARPU Experience with AI-assisted development workflows Prior experience at a fast-moving startup where you wore multiple hats 🙌 At Liftoff, You'll Enjoy Autonomy and Ownership: you are in charge of your time at Liftoff. Decide what you want to do, align with leadership, and go for it. Top-of-the-Market Cash & Equity Compensation: we pay for high performers. A World-Class Team: low-ego, high standards, and real ownership. 🤝 Interview Process Our interview process is designed to be thoughtful, efficient, and respectful of your time. Hiring Manager Screening Take-Home Challenge (backend task + experiment design prompt) Technical Deep Dive (live walkthrough + system design extension) Work week trial (paid - simulating real work environment) 💰 Compensation and Benefits Competitive cash + equity (based on scope and level) Company-paid lunch every day (if you're in office) Health & Wellness stipend up to $300/year Home office stipend available based on need Lifetime Liftoff Pro membership 🌍 Equal Opportunity Liftoff is an equal opportunity employer. We hire and grow talent based on strengths, potential, and performance, and we are committed to building an inclusive environment where everyone can do their best work.