Josie Nelder

Product engineer who ships end-to-end, including LLM systems.

I’m a senior full-stack engineer working in React, Next.js, TypeScript, Node and React Native, and I own features end to end, from the database to the interface. Lately that means AI products: a relationship coaching app whose voice sessions have been used 25,000+ times, and a detective game whose mysteries come from an AI pipeline I designed.

Selected work

  • Ember

    An AI relationship coach for couples. I work on the React Native app, the Next.js website and the backend API.

    • Web
    • API
    • Payments
    • AI
    • Design system
    • Mobile
    Role
    Senior Software Engineer
    Years
    2025–present
    Status
    Shipped
  • Cluedefy

    A detective game you play by typing your own questions. I built the app, its backend and the AI-assisted pipeline that helps write each mystery.

    • Web
    • API
    • AI
    • Data
    • Infra
    • Mobile
    Role
    Product, design and engineering, directing AI agents
    Years
    2026
    Status
    Launch-ready
    Cluedefy’s home screen in dark mode. An active case, Long Walk at Weldon Court, shows scene 1 of 6 with a Resume investigation button. Below it, the featured case, Non-Stop to Sandbourne, has an illustration of a steam train crossing the downs and is tagged Easy and Beta.
  • Habitual

    The app behind a UK weight-loss programme and NHS provider. I helped launch it as part of a very small team, then worked across its web and mobile apps and API.

    • Web
    • API
    • AI
    • Data
    • Mobile
    Role
    Senior Full-Stack Software Engineer
    Years
    2021–2025
    Status
    Shipped
  • Dog Walk Planner

    A Django and GraphQL API that plans dog walks around the weather, using Open-Meteo and postcodes.io.

    • API
    • Data
    Role
    Personal project
    Years
    2026
    Status
    In progress

About

I came to engineering the long way round. I studied biomedical science, took an MSc in genetic manipulation and molecular cell biology, and spent years supporting customers and clinicians at Apple, Fisher & Paykel and Roche. That’s where my focus on the people using what I build comes from.

Since 2019 I’ve built test frameworks, agency apps for healthcare and non-profit clients, a UK weight-loss programme’s app in a very small team, and an AI relationship coach.

Based in Brighton, UK.

Josie Nelder