Software Engineer — PureScript / Erlang

About Aykua

Aykua is a Cambridge-based, venture-backed startup developing AI systems to automate medical administration workflows accurately and efficiently. We are a lean, fast-paced team with significant opportunities to grow with the company.

The role

You'll own application delivery across our clinic, patient and internal-facing web applications, CLI tools and the APIs and data behind them. Working directly with the CTO as one of our first engineering hires, you'll turn agreed user needs into clear specifications, working features and reliable software in production.

You'll own application behaviour, feature quality, and diagnosis and fixes for the features you ship. The CTO provides technical direction and helps resolve decisions spanning the application and platform.

We use PureScript throughout production, targeting JavaScript and Erlang/OTP, with PostgreSQL, event-sourced systems, AWS, Nix/NixOS and Terraform/OpenTofu. Our UI uses the Elmish library, based on Elm. Prior PureScript experience is not required; strong functional programming foundations and willingness to learn our stack matter.

What you'll do

• Build features from accessible, responsive interfaces through APIs to the database.
• Develop backend services and third-party integrations, including PostgreSQL models, queries and safe schema migrations.
• Develop event schemas, projections, idempotent processing and replay.
• Use behaviour-driven development: define acceptance scenarios and write failing tests before implementation to independently verify agent-assisted changes. Use Playwright for user-facing acceptance and regression tests.
• Specify and coordinate substantial work with coding agents; review, debug and integrate their output yourself.
• Maintain representative, appropriately protected LLM and agent evaluation datasets, clear success criteria and reproducible benchmarks.
• Release, observe and support your features on shared AWS infrastructure and reproducible Nix-based environments, partnering with our production engineer.

What we're looking for

• Substantial professional experience taking web application features from user need to production, with increasing autonomy.
• Strong SPA skills: HTML, CSS, responsive layouts, accessibility, WebSockets, client storage and browser debugging.
• Practical functional programming experience, ideally in a typed language, and an understanding of static typing and controlled side effects.
• Backend and API development experience, including SQL and relational data modelling.
• Experience building reliable Playwright end-to-end tests and using test-first development to turn acceptance criteria into executable tests; no particular BDD framework is required.
• Experience directing coding agents through substantial implementation work: specifications, acceptance criteria, task coordination, independent testing, review and integration.
• Practical LLM or agent evaluation experience: representative datasets, useful metrics, model/prompt comparisons, failure analysis and quality/cost/latency trade-offs.
• Ownership of outcomes and disciplined engineering: automated testing, code review, source control and CI/CD, while maintaining quality, security and compliance.

Nice to have

PureScript, Haskell, Gleam, Erlang/OTP or another functional language; GitHub Actions; event sourcing and the actor model; relational database schema design; Nix/NixOS; AWS and Terraform/OpenTofu; WebCrypto, WebAuthn/passkeys or end-to-end encryption; healthcare integrations and compliance such as HIPAA, FHIR and HL7.

Location and compensation

Working timezone: Europe/London (UK time, GMT/BST).

Full-time, hybrid near Cambridge, UK, with regular in-person work and some remote flexibility. We could be flexible for the right person.

£55,000–£72,000 depending on experience, plus equity via stock options.

Interview process and applications

An initial call with one founder, followed by a formal interview with all founders.

Apply here on Wellfound with your CV and cover letter.

You must have the right to work in the UK or USA. We cannot offer visa sponsorship.