Original job description
🐘 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.
