Senior Fullstack Software Engineer - Ecosystem Experience in London

Senior Fullstack Software Engineer — Ecosystem Experience

At Semble, we are on a mission to enable health professionals to amplify their impact.

We improve the way healthcare is delivered to millions of people by providing doctors and their teams with powerful, innovative, intuitive, and secure software.

Our cloud-based clinical system is already used by thousands of clinicians, making their lives easier and saving them money, while structuring their health data to help research.

You’ll join our Ecosystem Experience team — the group that connects Semble to the wider healthcare ecosystem: labs, pharmacies, partner APIs, webhooks, and Semble Connect, our automation platform built on Workato.

We work closely with Product, Business, and external partners, and we ship in a large Type Script monorepo used across the company.

• We are a passionate and driven team, proud to unite under strong cultural drivers:
• Impact — We do work that matters.
• Collaboration — We are in it together.
• Human touch — We care deeply

We are also quick to embrace new technologies: we have rapidly adopted AI internally, and we are always looking to work with people who are excited to augment their work with AI.

This role can be fully remote in the UK and EU, with occasional travel to our London or Paris offices, within +/- 2 hours of the GMT time zone.

We are unfortunately not able to consider candidates located outside these locations and time zones at this stage.

What You Will Be Doing

As a senior engineer on Ecosystem Experience, you’ll own problems end to end — from partner discovery through design, implementation, rollout, and production reliability.

We expect you to operate with a high degree of autonomy and to raise the technical bar for the team.

• Lead the design and delivery of integrations that move clinical and operational data safely between Semble and external systems, including REST/Graph QL APIs, webhooks, HL7, SFTP, and i Paa S/automation flows.
• Work across the stack in our Yarn/Nx Type Script monorepo: React on the frontend, Node. js services and domain modules on the backend, Graph QL (internal and public APIs), and Mongo DB.
• Take ambiguous partner specs and product goals and turn them into clear technical designs, sequenced delivery plans, and clinically safe, testable solutions.
• Make sound architectural trade-offs — simplicity vs flexibility, build vs buy, speed vs long-term maintainability — and document the decisions so others can follow them.
• Own production outcomes: monitoring and alerting (e. g. Datadog), incident diagnosis, root-cause analysis, and durable fixes — not just shipping features.
• Improve reliability and operability: failure handling, retries, idempotency, credentials/secrets, multi-tenant config, and safe rollouts across many production environments.
• Contribute to Semble Connect and related automation — provisioning, connections, recipe/webhook patterns, and the product surfaces that expose them to practices.
• Set a high quality bar through design reviews, thorough code reviews, automated tests (unit, integration, e2e), and pragmatic CI/CD improvements.
• Mentor and unstick teammates; give clear feedback; help more junior engineers grow without becoming a bottleneck.
• Influence the Ecosystem Experience roadmap and technical standards — surfacing risks early, proposing better approaches, and aligning stakeholders when requirements conflict.
• What We Are Looking For

We’re looking for a senior fullstack engineer who enjoys messy real-world integrations as much as clean product UI — someone comfortable reading a partner Open API spec in the morning and shipping a resilient production path by the afternoon.

You should already be operating at a senior level: driving work independently, elevating those around you, and thinking beyond the ticket in front of you.

• Must-Haves
• 5+ years' professional experience building production web applications with React and Type Script, including substantial time operating as a senior / staff-of-one on complex features.
• Strong hands-on experience with Node. js backends and APIs (REST and/or Graph QL).
• Proven experience integrating with third-party systems — APIs, webhooks, auth flows, retries, idempotency, credentials/secrets.
• Ability to design systems, not just implement tickets: break down large problems, define interfaces/contracts, and leave codebases easier to change than you found them.
• Comfort working in ambiguity — clarifying requirements, challenging weak specs, and driving decisions when information is incomplete.
• A production ownership mindset: debugging complex issues across services, reading logs/metrics traces, and preventing the same incident twice.
• Solid automated testing habits (unit/integration/e2e) and comfort with CI/CD; you know when to add coverage and when not to over-engineer.
• Experience with No SQL databases (Mongo DB or similar) and cloud-hosted applications (AWS preferred).
• Strong written and verbal communication — RFCs/tech notes, partner discussions, and clear updates for Product and other engineers.
• Collaborative leadership without needing formal authority: mentoring, reviewing thoughtfully, and aligning people around a plan.
• Security and privacy awareness appropriate for handling sensitive healthcare data — least privilege, secrets hygiene, safe logging.
• Comfort using AI coding tools to accelerate delivery without lowering the quality bar.
• Strong Pluses
• Healthcare, HL7/FHIR, lab/pharmacy, or other regulated-domain integrations.
• i Paa S / automation platforms (Workato or similar).
• Design systems / component libraries, and large monorepo experience.
• Infrastructure as Code (Terraform / CDK), observability (Datadog or similar), and multi-tenant Saa S.
• Experience leading technical delivery across multiple engineers or workstreams.
• Playwright or Cypress e2e experience.
• Bilingual English–French.
• What You’ll Get in Return
• The great feeling coming with knowing you do something that matters: improving healthcare!
• £70,000–90,000 package, based on your experience and the value you can bring.
• Autonomy and ownership — we’ll set the vision and share the context, then we trust you to run with things – that’s the reason we hire you!
• 36 days off: 25 holidays + bank holidays + 3 extra days (birthday and ‘feel good’ days) — that we will expect you to actually take so you can recharge and rest.
• Company Equity — We appreciate and recognise all of our employees’ contributions, so everyone is eligible for Semble share options!
• Comprehensive health & wellbeing support — including private health insurance, and mental health support and free therapy sessions through Oliva.
• Hybrid & flexible work environment — work from anywhere in the UK, with also some flexibility to work across Europe. You decide how much or how little you go to the office.
• Get the tech you need — You will get the latest Mac Book (unless you prefer Windows) and take your pick across a wide range of equipment to setup your home office ergonomically.
• Work alongside an inspiring team — our two founders have started Semble after a successful startup exit, and your future colleagues are all knowledgeable and innovators in their field.
• Fantastic office space in Central London, right outside Monument — with a roof terrace, weekly activities, loads of natural light, and cute doggies!
• The usual free bits coming with nice offices — barista coffee, tea, fruits, happy hours and activities...