Contract Full-Stack Engineer (TypeScript / Python, AI Applications)

About the role
We’re looking for one contract developer to join a small team and push our product forward. You’ll work under our architect and founder, and you’ll be the muscle that turns specs into shipped, tested, monitored software. Most of the work is done autonomously during the day, with a product manager available as a touchpoint during normal hours (company Slack and all the usual systems are in place).

What you’ll do

• Take work from a written spec to production: build, test, ship and monitor it
• Develop and maintain our core platform (subscriptions, payments, sign-in, member data)
• Help build our upcoming AI coaching agent: retrieval, evals and prompt iteration
• Work with AI coding agents and review their output critically
• Flag blockers and risks early, in writing, and close the loop without being chased

Current stack

• TypeScript / Node.js (Fastify), PostgreSQL (Neon), pnpm monorepo
• Stripe (Checkout, subscriptions, webhooks) and WorkOS
• WordPress with custom PHP plugins
• Fly.io, GitHub Actions, Sentry
• Testing: Vitest, PHPUnit, Playwright, mutation testing

Coming next (AI coaching agent)

• Python, FastAPI, Pydantic AI, on Anthropic’s Claude models
• RAG: Postgres + pgvector, embeddings and reranking, ingesting documents and video transcripts
• LLM evals and observability (Langfuse)
• Next.js / React streaming chat app, Payload CMS, Drizzle

Must have

• Strong ownership and self-direction: unblocks themselves, communicates problems early in writing
• Strong TypeScript and Python, and solid PostgreSQL
• Real LLM application experience in production: retrieval quality, evals, prompt iteration on something used by real people (not just prototypes)
• Test-first discipline
• Comfortable working with AI coding agents while reviewing their output critically
• Care for security and privacy (the work touches payments and member data)

Nice to have

• Stripe or subscription billing experience
• Auth (WorkOS or similar)
• WordPress / PHP