Staff Backend Engineer
Do Health
Do Health is a mobile-first preventative health product, co-founded by Dr Rangan Chatterjee and built as an independent startup inside Voy - one of the UK's fastest-growing digital health companies (more than 100% YoY growth every year since inception, ~750k active customers across the UK, Germany, Brazil and India), already working across metabolic health, menopause, hormonal health, TRT and dermatology. Do Health is Voy's next chapter: the first product built not to treat illness, but to prevent it. We test people's blood regularly, track how it changes over time, and turn results into a personalised programme across four pillars - Eat, Move, Sleep, Relax - that helps someone make small changes they can actually keep.
Staff Backend Engineer
Do Health - London, Hybrid (3 days/week in person) Why this role exists
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. Voy is one of the UK's fastest-growing digital health companies (£600M+ revenue, doubling next year, ~2x YoY growth across men's health, metabolic health, menopause, hormonal health, TRT, dermatology and more). Do Health is its next chapter: the first product designed not to treat illness, but to prevent it. The product combines regular blood tests, longitudinal health data, behaviour-change science and AI personalisation to help people make better lifestyle decisions over time. We already run AI systems in production at a scale very few UK companies match. You'd join a 10-person team, partnering directly with our lead engineer on the backend. There's no layer of management between you and the work. What you ship in month one is what users get. What you'll actually do
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.
The kind of engineer this works for
You'll fit if you have: 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, not required: 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
Why this might be the right move
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.
Practical details
Location: London
Working pattern: Hybrid, ~3 days per week in person
Compensation: Competitive - happy to discuss bands early in the process
Process: Intentionally short. Hiring manager interview, technical conversation, team chat. We move fast for the right person.
If you've read this far and any of it resonates, we'd like to talk - even if you're not actively looking.
Staff Backend Engineer
Do Health - London, Hybrid (3 days/week in person) Why this role exists
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. Voy is one of the UK's fastest-growing digital health companies (£600M+ revenue, doubling next year, ~2x YoY growth across men's health, metabolic health, menopause, hormonal health, TRT, dermatology and more). Do Health is its next chapter: the first product designed not to treat illness, but to prevent it. The product combines regular blood tests, longitudinal health data, behaviour-change science and AI personalisation to help people make better lifestyle decisions over time. We already run AI systems in production at a scale very few UK companies match. You'd join a 10-person team, partnering directly with our lead engineer on the backend. There's no layer of management between you and the work. What you ship in month one is what users get. What you'll actually do
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.
The kind of engineer this works for
You'll fit if you have: 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, not required: 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
Why this might be the right move
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.
Practical details
Location: London
Working pattern: Hybrid, ~3 days per week in person
Compensation: Competitive - happy to discuss bands early in the process
Process: Intentionally short. Hiring manager interview, technical conversation, team chat. We move fast for the right person.
If you've read this far and any of it resonates, we'd like to talk - even if you're not actively looking.
Reference: WJCPA-5429_434749 · Posted 13 Nov 2026, 01:16 AM