About the Role
We're hiring a Staff Backend Engineer as a part of the founding team at Do Health - a mobile-first preventative health product co-founded by Dr Rangan Chatterjee, built as an independent startup inside Voy.
Responsibilities
•Own major backend features end-to-end - design, build, ship, monitor, iterate. Not "contribute to" - own.
•Shape architecture. Real technical decisions, made by you, kept or changed based on what works.
•Scale our blood testing infrastructure across the UK and internationally as we expand.
•Build production AI systems - personalisation engines that act on longitudinal health data at scale.
•Improve reliability, observability, and the foundations that everything else depends on as the product grows.
•Work directly with product, design, and clinical teams. No tickets thrown over walls.
Requirements
•7–9 years of backend experience with strong fundamentals. We care more about depth than years.
•Experience at a startup or scale-up where you genuinely owned things.
•Architectural thinking. You can hold an end-to-end technical conversation about systems you've built — what trade-offs you made, what broke, what you'd do differently.
•A track record of shipping reliable systems. Not just features — the boring infrastructure that keeps them up.
•Comfort with judgement calls in ambiguous situations. Most decisions here don't have a clear right answer.
•Confident, responsible use of AI tools in your workflow. Not "vibe coding" - using them as a force multiplier where they help, ignoring them where they don't.
Nice to Have
•Strong TypeScript / Node.js experience (it's our primary stack, but we'll happily hire someone excellent in Go, Kotlin, Python or similar)
•Experience scaling systems to high user volumes
•Exposure to ML/AI systems in production
•Healthcare or regulated-industry experience
What We Offer
•Genuine equity in a product with real upside, not lottery-ticket equity at a company that may never exit
•Startup velocity with grown-up backing - Voy isn't going anywhere, so you're not betting your mortgage on Series A survival
•A product that matters. Preventative health is one of the few areas where building software actually changes outcomes, not just engagement metrics.
•A high technical bar from day one. You're not joining a team that needs convincing to do things properly.
•Direct access to leadership - your work, your decisions, your name on them.
