Senior Staff Full Stack Engineer

Healf was founded by two brothers - Max and Lestat - with a relentless drive to reshape health and wellness. Their journey has been fuelled by hard work, intensity, and a commitment to build something transformative. Like all of us, they’re here to make a lasting impact. Build the Future of Wellbeing Do Your Life’s Best Work If modern wellbeing were redesigned from scratch, it wouldn’t live in a GP’s office or a cluttered supplement aisle. It would be digital-first, beautifully curated, and powered by data that actually helps you feel your best. That’s what we’re building at Healf. An ecommerce platform at the intersection of personalised health and curated wellbeing. We connect customers with the world’s most effective products across EAT, MOVE, MIND, and SLEEP, and we’re just getting started. We combine culture-shaping storytelling, cutting-edge health tech (like our new blood testing platform, Healf Zone), and a best-in-class product experience to help people build rituals that work. Backed by investors behind Soho House, Alo Yoga, Cult Beauty, and Innocent, we’re scaling fast, and redefining how the world shops and lives well. About Us At Healf, we’re not just a company, we’re a movement. Founded by two brothers whose own wellbeing journeys inspired our mission to empower others, Healf is built on grit, determination, and a shared understanding of the power of wellbeing. Our culture is grounded in The Healf Standard—five principles that define how we work and win: • We Work Harder Than Anyone Else : Building something that improves lives takes long hours, grit, and sacrifice, but we thrive on it. We all feel energised by what we’re building. • Never Settle : We challenge the status quo and push ourselves to be better every day. We never settle for mediocrity or the idea that something can’t be done. • Obsession Over Talent : Talent alone isn’t enough—relentless curiosity and a drive to grow set us apart. • The Healf Lifestyle : We live what we preach—our personal commitment to wellbeing fuels our professional productivity. • Stronger Together : Everyone owns their lane, but we run as a unit. With Healf Zone on the horizon, we’re entering the next phase of our journey: closing the loop on health with personalised, preventative care that unlocks longevity and optimised wellbeing. This is your chance to help build something that’s not only extraordinary, but a first of its kind. The Role We're scaling rapidly across Web/Frontend and Backend/AI. To keep pace, we need a hands-on technical leader who can balance deep execution with architectural foresight. You'll bridge strategy and implementation: co-creating architecture and engineering standards with the Head of Engineering, while directly leading teams to build systems that scale sustainably—without bottlenecks. Location: Remote — Open to candidates based anywhere in the UK. Key Responsibilities • Own architecture & systems design . Define high-impact decisions across frontend and backend (service boundaries, data flows, ADRs, UI composition, BFF patterns). Evolve our API and event-driven designs for scale and reliability. • Lead execution end‑to‑end. Drive projects from discovery → design → implementation → production. Align scope with Product & Design, surface trade-offs early, and keep teams unblocked. • Build excellent services . Ship robust Python/FastAPI  microservices and TypeScript/React (ideally Next.js ) frontends. Use Node.js  (Express/Fastify/NestJS) for BFFs/edge services where it fits. Back with PostgreSQL/Redis/Elasticsearch (or OpenSearch ) for performance, resilience, and cost efficiency. • Asynchronous comms at scale . Design and implement async workflows (Kafka/SNS/SQS/EventBridge), sagas/outbox, idempotency, retries, and back‑pressure; champion distributed tracing and well‑defined contracts. • Infrastructure as code . Stand up and evolve AWS  with Pulumi/Terraform (VPC, ECS/EKS or Lambda, API Gateway/ALB, CloudFront), manage secrets and networking, and automate CI/CD  (GitHub Actions/ArgoCD). Use CDNs/edge where appropriate (e.g., CloudFront/Cloudflare/Vercel). • Observability & Reliability . Establish SLIs/SLOs. Integrate logs/metrics/traces (OpenTelemetry, Prometheus/Grafana/Datadog/Sentry). Add frontend observability  (RUM, error tracking, Core Web Vitals), and drive actionable alerts and incident reviews. • Security & Governance . Apply AWS Well-Architected, least-privilege IAM, secret management, SDLC controls, and OWASP-aware web security (CSP, CSRF, SSRF mitigations). Partner on data/privacy (e.g., GDPR). • Mentor & Uplift . Lead through design walkthroughs, pairing, and code reviews across frontend and backend. Help engineers level up and take on bigger problems. • Greenfield & Modernisation . Lay foundations for new domains (mobile backend, new verticals) while improving existing systems (performance, reliability, cost). Guide migrations (e.g., to RSC/Next.js App Router, typed APIs)• Team Leadership . Set engineering standards, facilitate technical planning, coordinate across squads, and influence hiring/interviews. Provide calm, decisive technical leadership. • Cross‑functionally . Turn business goals into pragmatic technical plans; communicate trade-offs clearly to non-engineers.Qualifications • Deep Backend Mastery : Python 3.x, FastAPI/Flask; SQL schema design & query performance; caching strategies; robust testing (pytest, property-based, integration). • Frontend Capability : Strong TypeScript/React  (Next.js preferred), component architecture, state/data fetching (TanStack Query), forms, accessibility (WCAG 2.1), performance (Lighthouse, Web Vitals), and SSR/SSG/ISR. • Node.js experience : Building BFFs/edge APIs with Express/Fastify/NestJS; API design (REST/JSON; bonus for GraphQL/gRPC); familiarity with tRPC a plus. • Modern Microservices : Event-driven patterns, resilience (circuit breakers, bulkheads, timeouts), contract testing, and API versioning. • Cloud & IaC : Strong AWS  (networking, compute, storage, security). Production Pulumi and/or Terraform. Containers (Docker ) and orchestration (ECS/EKS ) or serverless where it fits. • Data & Search : PostgreSQL at scale; working knowledge of Elasticsearch/OpenSearch (indexing, relevance, aggregations). • Observability Culture : You've stood up tracing/metrics/logging from scratch and used them to drive reliability—both backend and frontend. • Leadership through Craft : Excellent taste in code, clear docs/ADRs, and steady decision-making. Proven mentorship and leading multi-team initiatives. • Bias for Delivery : You break down complexity, make smart trade‑offs, and ship. Nice to Have (Not Required): •  Design systems (Storybook), Tailwind/Chakra, advanced forms (React Hook Form/Zod). • GraphQL (schema design, federation), tRPC, Prisma/SQLAlchemy. •Vector search/retrieval, ML-adjacent pipelines, feature flags/experimentation. • WebSockets/WebRTC, background jobs/cron orchestration. • Performance profiling (backend & frontend), cost-aware architecture. •Experience with LangChain/agents—useful, but optional . Why Join Healf • Do your life’s best work: Build something that matters, with a team that moves fast and aims high • Surround yourself with A+ talent : You’ll work with high-performers who care deeply and raise the standard every day • Be a builder : This isn’t a cog-in-the-machine role. You’ll help shape our voice, culture, and growth • Wellbeing is the lifestyle : From office yoga to Healf Zone insights, everything we do is rooted in our pillars: EAT MOVE MIND SLEEP • Premium Wellhub Membership : Unlimited entry to 1000's of gym, yoga, & fitness studios (UK Only) • Exclusive Healf Perks : 50% off all Healf products plus discounted Healf Zone blood testing. • Nest Pension : Secure your future with our pension contributions. (UK Only)• Wellbeing-Focused Workspace : Incredible Hammersmith office with great natural lighting (Optional Workspace if UK-Based) • Team Connection : Annual company-wide retreat to recharge and bond.