Portfolio

James Day Co-founder & COO Growth · Lifecycle · Acquisition

The work I do best moves curves, not points. That means living where product, ops and commercial meet.

As COO of Old Gold Racing — the DTC racehorse ownership platform I co-founded in 2019 — I led all three from day one, helping grow the business from zero to £3.27M.

AI means the work of an operator now includes building what they used to brief out. This page details the sorts of things I can build with AI, as well as giving you a taste of how I think.

James Day
Projects

Things I've built.

Each project below was built solo, from end-to-end (from brief to live URL) using modern AI-assisted workflows.

Cooky Jar app logo
01 / 03

Cooky Jar

A full-stack PWA for meal planning, recipes and shopping. Engineered for security, performance, and household-to-household viral growth. Built solo, AI-assisted, from Figma design to live deployment.

  • React + TypeScript, vercel serverless API and Neon Postgres persistence.
  • Per-household auth with scrypt-hashed passphrases and signed JWT sessions.
  • Claude-API recipe recommendations over a cached, dead-link-filtered web search.
  • Single-use invite links and account-to-account sharing power viral growth.
View the web app View demo account
Analytics dashboard on a laptop screen
02 / 03

Dashboard Build

A subscription-analytics dashboard for a fictional meal-box brand: cohort retention, MRR build-up and channel LTV:CAC economics. Static JSON, deployed on Vercel from GitHub and built with Claude Code

  • SQLite data model over a ~3K-customer synthetic dataset
  • Modular query → API → render layers with time-windowed analytics
  • Chart.js cohort-retention, MRR and LTV:CAC views plus contribution-margin slider
  • Client-side SQL playground via SQLite compiled to WebAssembly
View the dashboard
MacBook with code on screen
03 / 03

This Website

Designed in Figma, then engineered through AI-assisted agentic development. Pixel-faithful, accessible, and editable from any device in production. A component-driven Astro front end wired to a git-based CMS.

  • Figma design ported into Claude Code over MCP (exact tokens)
  • Astro front end, minimal JavaScript, CSS-custom-property design tokens.
  • Serverless on Vercel with SSR adapter; Formspree-backed contact form.
  • Git-based Keystatic CMS in GitHub mode
How I Work

Four operating principles.

Growth is built

The acquisition channels that last have low CAC at a high scale. I tend to find them by building, not buying — freemium activation, B2B2C partnerships, product-led loops.

Quality drives retention

The biggest retention lift I've driven came from a product upgrade, not running a campaign. I treat retention as an upstream operations problem with marketing symptoms.

Economics inform action

Unit economics aren't just the outputs I report on, they're the inputs I plan from. The growth model is the brief. At OGR, redesigning the breakeven economics unlocked sustained profitability.

Learning velocity wins

Closing the loop between hypothesis and evidence is where most growth wins lie. Customer empathy, intellectual rigour and rapid, AI-driven iteration are what gets us there.

READING

Books I've loved.

In no particular order, here are ten books that have informed my thinking over the years.

01 Fooled by Randomness Nassim Nicholas Taleb
02 High Output Management Andy Grove
03 This Is Marketing Seth Godin
04 The Culting of Brands Douglas Atkin
05 Delivering Happiness Tony Hsieh
06 The Master and His Emissary Iain McGilchrist
07 The Fear of Freedom Erich Fromm
08 Good Strategy Bad Strategy Richard Rumelt
09 Good to Great Jim Collins
10 Continuous Discovery Habits Teresa Torres
Contact

Let's set up
a call.

If you're looking for a growth marketer who can think strategically and build operationally, I'd be glad to talk. Drop me a message and I'll get back to you promptly.