Senior Full-Stack Engineer, Perci

• Around 6+ years building software end to end, ideally in TypeScript, Node.js and React. We are open to adjacent stacks where the fundamentals are strong
• Substantial experience of system design and architecture, including systems that have been in production long enough to show their weaknesses. We will ask you to talk us through something you have designed, what went right, what went wrong and what you would do differently
• Practical experience of distributed systems and third-party integrations, including auth, webhooks, rate limits, retry strategies, fault tolerance, transaction management and the various quirks that come with them
• Strong testing ability and practice, developed through enough experience to be able to look at a design and identify where it is likely to fail
• You have used AI coding agents on production work and have an informed view of where they help and where they do not
• Comfortable working both autonomously and collaboratively, with a positive influence on the engineers around you
• Candidates will be assessed against the following essential criteria:
• You are pragmatic about technology and about how software gets built. You hold your preferences for reasons and you are able to recognise when those reasons no longer apply
• You are comfortable with ambiguity and incomplete information, and you have your own methods for unblocking yourself where there is a lack of clarity rather than waiting for someone else to provide it
• You are open to experimentation, including working in ways you have not worked before. It is quite reasonable to expect that some of what we try will not work
• You have worked in a small team, where requirements are not fully specified and delivering means filling the gaps yourself, or working out how they should be filled
• You are able to think on paper, and can describe a system in writing precisely enough that another engineer, or an agent, could build it from your description
• You are a clear and confident communicator. We are fully remote, so you will need to run stand-ups, raise concerns where something looks wrong, and keep people working towards the same objective
• You have a clear motivation to build products that benefit people, and it is evident in how you work

Desirable

• We are hiring a Senior Full-Stack Engineer to build Perci's platform, and at the same time help us shift how that platform gets built. The platform is how our members reach their care, often at a point when they need it most
• Today we work conventionally; a specification is written, an engineer builds it, another reviews it. We think that is changing, with far more of the code written by AI agents, and we intend to be early to it
• Most engineering practice assumes that writing code is the expensive part, which is why we favour reuse over rewriting. As that cost falls, the value moves towards deciding what to build and proving it was built correctly. Working out what that means for us is a significant part of this role
• You would be joining a team doing recognisable full-stack work on a live product, with patients using it and delivery dates to meet. Part of the role is helping us move from where we are today to where we believe we need to be
• This is one of our first permanent engineering hires. You will report directly to the CTO and work alongside a small group of senior engineers
• The work as it is today:
• Design, build and ship features end to end, from data model and API design through to frontend implementation
• Design and build robust, scalable APIs in TypeScript and Node.js, published in OpenAPI format
• Architect resilient distributed systems and third-party integrations, with sound error handling, failure mode mitigation and transaction control
• Work with FHIR R4 resources and clinical data models within Medplum
• Contribute to our frontend rewrite as we move from Flutter to React
• Make sensible build-versus-buy decisions; we build only what creates differentiated value for Perci and source the rest
• Own the testing of your own work, and contribute beyond your core discipline. We are a small team, so everyone picks up QA and DevOps work
• Ensure our development practices meet the requirements of the regulatory context. We build software as a medical device and the consequences of getting it wrong are more significant than in most products
• The work we are building towards:
• Write specifications precise enough that an agent can implement them and that you can verify the result against them. We treat this as core engineering work rather than documentation overhead
• Consider verification at the same time as the specification; how we would know the change was built correctly and where it is likely to fail
• Help build the tooling and controls that allow agents to work safely, covering risk-based review, monitoring, alerting, incident response and automated pre-release verification
• Help us determine where agent-authored change can be released directly to production and where it cannot, bearing in mind that this judgement has clinical consequences
• Set the standard and help define the practice for how we do all of this