Lead Mobile Frontend Engineer

About the role

Calibrex is on a mission to democratize fitness coaching by giving everyone access to a world-class personal trainer for less than the cost of Netflix. We’re building GPS-like guidance for fitness: clear direction at every step, without excuses or guesswork. All you have to do is show up. As a Lead Mobile Frontend Engineer, you’ll help build the product that makes this mission possible. You’ll work directly with athletes, influencers, and leaders across fitness and professional sports while shaping the UX and direction of the app.

You’ll also work out in our office gym, collaborate with an elite team in one of the fastest-growing spaces in technology, and enjoy high-protein catered meals, a premium gym membership at Life Time or Equinox, and an office located three blocks from Grand Central.

Calibrex offers an annual performance-based cash bonus and a generous equity package. The role includes great benefits and is an excellent wealth-building opportunity at a fast-growing pre-IPO company in a nascent and extremely exciting space.

Requirements

• 3+ years of professional experience developing mobile applications
• Experience building or maintaining mobile apps used by 100,000+ users
• Strong React Native and TypeScript experience
• Ability to turn Figma designs into polished, production-ready mobile flows
• Strong understanding of React hooks, API calls, asynchronous data, state management, and error handling
• High standard for mobile performance, usability, and interaction quality
• Comfort using AI tools for development, prototyping, debugging, and testing
• Ability to work independently and provide technical leadership
• Strong communication and collaboration skills
• Must regularly work out or train and be comfortable testing the app in our office gym; this is an essential part of the role

Skills

• React Native
• Expo/EAS
• Github
• Figma to Code
• React hooks
• API integration
• State Management
• AI-Assisted Development
• Loop Engineering
• Mobile Testing
• Firebase

Preferred experience

• Shipped a consumer mobile app at meaningful scale
• Used Expo
• Led frontend architecture or mentored other engineers
• Built automated mobile testing or performance-monitoring workflows
• Worked at an Early-Stage startup
• Contributed to product strategy or UX direction

Benefits

• High-protein catered meals
• Premium gym membership at Life Time or Equinox
• Office located three blocks from Grand Central
• Annual performance-based cash bonus
• Generous equity package