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 they develop healthier, more powerful habits.
We’re a mission-driven team that moves fast, owns the details, and does the work. We’re fully bootstrapped, profitable, and built from zero to $8M+ ARR in under two years.
🌟 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 ship product features and experiments end-to-end. Your core focus areas:
Feature delivery across the stack in TypeScript, from React Native screens to Supabase data
Polished, correct UI, shipped to the standard of the design, not an approximation of it
Experiment infrastructure and instrumentation
Clean, performant API and data access
Cross-functional shipping with Product, Design, and Growth
This is a high-ownership role. You'll take a problem from spec to shipped, work with our existing team/resources, and own the outcome, not just your slice of it.
✅ What Success Looks Like
Features and experiments that go out end-to-end without stalling on handoffs
UI that ships pixel-correct and feels right; spacing, states, edge cases, and transitions handled without needing a review pass to catch them
A high-velocity experiment pipeline: clean instrumentation → fast implementation → reliable measurement → iteration
A product that stays fast and stable as usage grows; schema changes land safely, queries stay efficient
Shipped 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
Ship features end-to-end
* Build the front end in TypeScript with React Native (Expo); typed, readable, and maintainable by the next person
* Implement designs faithfully: correct spacing and type, all states (loading, empty, error), and the edge cases the mock doesn't show
* Write and run migrations and deploy schema changes safely; keep the data model clean as the product grows
* Stay conscious of load and performance - catch the slow query or the runaway request pattern before users do
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 full-stack experience shipping to production
Strong TypeScript - it's the language of the whole stack here, front end included
Comfort on both sides: modern front-end (React / React Native or similar) and Node.js against a relational database (Postgres preferred)
A real eye for detail; noticing unwanted 4px gaps, missing empty states, animation stutters, and fixing it without being asked
Working knowledge of schema design, migrations, and query performance, enough to make changes safely without needing a specialist
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
UX instinct - you can tell when a flow doesn't feel right, not just when it doesn't match the spec, and you can articulate why and push back on a design
Experience with our specific stack: Supabase, Vercel, tRPC, Statsig, RevenueCat
Background in subscription/consumer apps - understanding of trials, paywalls, LTV, ARPU
Experience with AI-assisted development workflows
Motion/animation implementation (Rive or similar)
🧰 Tools & Tech Stack
Language: TypeScript, end to end
App: React Native (Expo)
Frontend: Figma, Rive
Backend: Supabase, Vercel, tRPC, Node.js
Monetization: RevenueCat, Superwall
Experimentation / Analytics: Statsig
🙌 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 + frontend implementation)
Technical Deep Dive (live walkthrough + system design extension)
Work week trial (paid - simulating real work environment)
💰 Compensation and Benefits
Competitive cash (based on level and scope)
Company-paid lunch every day (if you’re in office)
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.
