Senior Staff Full Stack Engineer

<h2><strong>Build the Future of Wellbeing</strong></h2><h3><strong>Do Your Life’s Best Work</strong></h3><p>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.</p><p>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.</p><p>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.</p><p>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.</p><h3>About Us</h3><p>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.</p><p>Our culture is grounded in The Healf Standard—five principles that define how we work and win:</p><p><strong>• We Work Harder Than Anyone Else</strong>: 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.</p><p><strong>• Never Settle</strong>: 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.</p><p><strong>• Obsession Over Talent</strong>: Talent alone isn’t enough—relentless curiosity and a drive to grow set us apart.</p><p><strong>• The Healf Lifestyle</strong>: We live what we preach—our personal commitment to wellbeing fuels our professional productivity.</p><p><strong>• Stronger Together</strong>: Everyone owns their lane, but we run as a unit.</p><p>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.</p><h3><strong>The Role</strong></h3><p>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.</p><p><strong>📍Location: Remote — Open to candidates based anywhere in the UK/EU Time Zones.</strong></p><h3><strong>Where You’ll Make An Impact</strong></h3><p>• <strong>Own architecture &amp; systems design</strong>. 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.</p><p><strong>• Lead execution end‑to‑end.</strong> Drive projects from discovery → design → implementation → production. Align scope with Product &amp; Design, surface trade-offs early, and keep teams unblocked.</p><p><strong>• Build excellent services</strong>. Ship robust <strong>Python/FastAPI</strong> microservices and <strong>TypeScript/React</strong> (ideally <strong>Next.js</strong>) frontends. Use <strong>Node.js</strong> (Express/Fastify/NestJS) for BFFs/edge services where it fits. Back with <strong>PostgreSQL/Redis/Elasticsearch</strong> (or<strong> OpenSearch</strong>) for performance, resilience, and cost efficiency.</p><p><strong>• Asynchronous comms at scale</strong>. Design and implement async workflows (Kafka/SNS/SQS/EventBridge), sagas/outbox, idempotency, retries, and back‑pressure; champion distributed tracing and well‑defined contracts.</p><p><strong>• Infrastructure as code</strong>. Stand up and evolve <strong>AWS</strong> with <strong>Pulumi/Terraform</strong> (VPC, ECS/EKS or Lambda, API Gateway/ALB, CloudFront), manage secrets and networking, and automate <strong>CI/CD</strong> (GitHub Actions/ArgoCD). Use CDNs/edge where appropriate (e.g., CloudFront/Cloudflare/Vercel).</p><p><strong>• Observability &amp; Reliability</strong>. Establish SLIs/SLOs. Integrate logs/metrics/traces (OpenTelemetry, Prometheus/Grafana/Datadog/Sentry). Add <strong>frontend observability</strong> (RUM, error tracking, Core Web Vitals), and drive actionable alerts and incident reviews.</p><p>• <strong>Security &amp; Governance</strong>. 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).</p><p>• <strong>Mentor &amp; Uplift</strong>. Lead through d