Stamina is looking for a Founding Engineer (Full Stack) 
Location: Based in Europe, and willing to relocate to, our future HQ in London or Amsterdam.
The company
Stamina is bridging the gap between static training plans and coaches. Since launching in October, weâve grown to a user-base of thousands of athletes worldwide, purely through the quality of our product, in-house social media, and word-of-mouth. Our MRR is growing ~15% WoW and we havenât spent a dime on paid marketing.
Weâre making intelligent training planning accessible to everyone by building an engine that adapts to the realities of the modern athleteâs life.
But weâre not just building a smart algorithm. We believe software should be as beautiful as it is functional. An app that actually inspires you to train. Our bar isnât âgood enough.â, we want to build something people genuinely love to use. Maybe even App of the Year one day.
The role
Weâre a small team with two engineers (Technical Founder/CTO + one founding engineer), and weâre looking for another Founding Engineer to complete our core product team.
This is a high-ownership role. You wonât just be picking up tickets, youâll help shape the product, the architecture, and the company alongside us.
We take the work seriously, but not ourselves. We train together, argue about UX and our IG reels, and care deeply about building something weâre genuinely proud of.
The challenges
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Adaptive algorithms: Work on the logic behind our training engine, constraint solvers that dynamically manage progression, fatigue, and scheduling.
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Data science & insights: Find creative ways to use training data, spotting patterns in performance and recovery to deliver insights athletes didnât know they needed.
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Fluid interactions: We use React Native (Expo), NativeWind, and Reanimated. We sweat the details on animations, gestures, and micro-interactions so the app feels native, fast, and delightful.
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Device ecosystem: We integrate deeply with Garmin and Strava, with more to come. Building reliable sync and normalising data across platforms is a core part of our backend (Node.js/TypeScript, Supabase).
Youâre a great fit ifâŚ
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Youâre an endurance athlete: You run, bike, or swim every week, ideally all three.
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You believe clean code is leverage: You care about elegant data models and simple abstractions because they help small teams move fast without stepping on each other.
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You sweat the details: You notice when somethingâs off - a janky loading state, glitchy animations, or a font weight feels wrong.
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You pride yourself on your Taste: Without sounding pretentious, you see yourself as an artist as well as an engineer. You have strong instincts for UX and design. You know what you like, and you take pride in shipping products that are beautiful and intuitive.
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Youâre a clear communicator: You can explain your thinking, back up decisions with data or logic, and enjoy thoughtful discussion.
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Strong beliefs, weakly held: Youâre passionate about your ideas and taste, but youâre open to changing your mind when you hear a better argument.
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You value autonomy: You thrive in an environment where you define your own work and take ownership.
The offer
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Meaningful equity reflecting the founding nature of the role
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Early-stage startup salary with substantial upside as the company grows
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Hybrid work 3-5 days in the office
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Flexible hours so you can train when you want (with a pinch of
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Gear stipend (merch, race entries, etc.)
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Annual Stamina training camp in southern Europe
How to apply
Email us at careers@joinstamina.com with the following:
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A link to something youâve built that youâre proud of
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Your resume or LinkedIn
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1-2 sentences on your interest in endurance sports / triathlon
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Pick a feature or flow in any app/website you use that frustrates you. Explain why you think it was built that way (the likely constraints, trade-offs and decisions), and how you would redesign it to be better.
We aim to respond to every application within 72 hours.
Thanks for your interest!