Remote - Senior Full-Stack Engineer (Mobile-First Health App)

We're an AI-powered adaptive fitness platform that launched in 2026 and is now in growth phase. We're a small, fast-moving team replacing an outside agency with a focused in-house contractor crew. You'll work directly with our lead engineer and founder, so ownership and judgment matter as much as code.

You will own core backend systems and ship features end to end. This is a build-and-maintain seat, not a ticket-taker role.

What you'll work on

• Workout and nutrition engine logic (time estimation, prescription parameters, structured data pipelines)
• Third-party integrations: Stripe, RevenueCat, Zendesk, and nutrition data APIs (FatSecret)
• API design, backend architecture, and data modeling
• Mobile-facing feature work in close coordination with design
• Performance, reliability, and clean handoffs

What we're looking for

• 5+ years full-stack experience, with real backend depth (not frontend-leaning)
• Proven track record shipping production features independently
• Experience with subscription and payment integrations (Stripe, RevenueCat a strong plus)
• Comfort owning architecture decisions and explaining your reasoning
• Strong written English and async communication
• Prior remote work for US or Western European companies preferred

Nice to have

• Health, fitness, or wellness app experience
• Experience with mobile app backends at consumer scale
• Familiarity with HIPAA-adjacent or health data handling

How we hire

1. Short intro call (30 min)
2. Technical conversation about past work and architecture choices
3. Paid trial task pulled from our real backlog (1–2 weeks)
4. 30-day paid trial engagement, then ongoing contract

We move fast and we pay for trial work. We care about delivered output, not hours logged.