Jay Stewart

Available now for remote contract work

I find out what users need, then ship it with coding agents.

I'm Jay Stewart, a product engineer. I work across the whole product: talking to users, design, code, payments and running it in production. I'm looking for contract work with early-stage startups.

Email me How I work with clients CV (PDF)

UK citizen, UK-registered sole trader. Overlaps UK afternoons and US working hours.

3products shipped since March 2026
2live in production, one taking real payments
8 yearsof e-commerce backends before, including Dyson's store

Selected work

SpiralClass

Live · real payments

Scheduling, payments and video for independent teachers. Built and run solo; in production with a teacher and her eight students.

  • Stripe Connect direct charges on the teacher's own account, so the platform never holds the money. Wise as a second rail, reconciled through its API.
  • About 870 test files and one definition of green, run the same way locally and in CI, including real-database integration tests and a migration drift check.
  • Nearly 150 decision records, several of them reversing an earlier call and saying why.
  • TypeScript
  • Next.js
  • Postgres
  • Prisma
  • Stripe Connect
  • Wise
  • LiveKit
  • Inngest

Read the case study → · Live demo · Source

WantToJoin

Pilot · one hostel

A page per hostel for tonight's outings and who's going. Before writing code I read 2,800 messages from a hostel's guest WhatsApp group. They showed that the hosts, not the guests, were the people to build for.

  • From research to a live pilot at that hostel in three days.
  • An AI post writer drafts every post in English and Spanish, checked in code. All 50 eval drafts pass, at about $0.0003 a post.
  • Pilot results, good or bad, published after it ends on 14 October.
  • Cloudflare Workers
  • D1
  • PostHog
  • Claude Haiku

Read the case study → · wanttojoin.com

Beckon

Live · October 2026

A remote inbox for terminal agents. Your phone tells you when Claude Code or a build is waiting, and you approve or deny from the lock screen.

  • End-to-end encrypted. The helper only types a response signed by a device you paired with a six-word safety code.
  • A Go helper, a Next.js and WebSocket service, and an installable web app with push notifications.
  • Runs on one hardened VM with monitoring, a dead man's switch and tested, encrypted offsite backups. Stripe billing is live; no outside users yet.
  • Go
  • TypeScript
  • Next.js
  • Postgres
  • WebSockets
  • Web Push

Read the case study → · beckoncli.com · Source

How I work

  1. Start with users.I talk to them, read what they actually say, and change the plan when the evidence points somewhere else.
  2. Experiments have a stopping rule.The hypothesis, what to measure and when to stop are written down before any code.
  3. I own what the agents write.I build with coding agents, and every change goes through a pull request, tests and a check in a real browser.

Before this

  1. Independent product engineerSpiralClass, WantToJoin and Beckon, built largely with coding agents.
  2. Career breakA planned six-year break, travelling on savings. Back in March 2026 because coding agents changed what one person can ship.
  3. G&V | Venture Brands AgencyContract backend engineer on high-traffic e-commerce, including Dyson's store.
  4. Thrive ChiropracticDesigned, built and ran a booking and payment platform for nearly four years.
  5. Folk DigitalBackend features and integrations for e-commerce clients.
  6. C3 MediaFrom junior PHP developer to building full e-commerce systems on my own.

Need a first version, or a second pair of hands?

Email me what you're building and what you need first. Within a working day I'll reply with whether it fits and what the first two weeks could look like.

Email jay@jaystewart.co.ukHow an engagement works