Oli Treadwell

Senior Software Engineer & Accessibility (A11y) Advocate | Wellington, NZ

About Me

I'm a software engineer with ten-plus years of building things for the web. I was British born, California raised, and Texas aged, with stops in Chicago, Los Angeles, and Melbourne along the way. These days I'm based in Wellington, New Zealand, working at Numeral Studio where I write React, Next.js, TypeScript, and Node.js most days.

I got into tech through startups. I spent time around angel investing, VC, and coworking spaces before co-organising Startup Weekend events and running tech meetups like Refresh Austin and Silicon Beach Melbourne. Eventually I retrained as a software engineer so I could build my own apps if I ever needed to. I've spent most of my career as an engineer rather than an entrepreneur, but that startup background has followed me the whole way.

I care about making the web work for everyone, not just the people who happen to have fast connections and perfect vision. That interest led me to develop a framework I call "The Cognitively-Kind Web," focused on accessibility for diverse cognitive processing styles. Alongside production engineering work, I've spent years building engineering team capacity at enterprise companies across the USA through structured technical training, ongoing mentoring, and code-review-based coaching. That work has included around 400 engineers at Amazon and hundreds of pull-request reviews that directly shaped how engineers ramped on new stacks and shipped production work.

When I'm not at a keyboard I'm usually out with a camera. You can see some of that work on Instagram. I like live music, exploring a new city without much of a plan, cycling, roller skating, dancing, and trying to get better at cooking. I grew up in San Diego, went to university at Chapman in Orange County, and picked up a bit of everything from the places I've lived since. I finished a postgrad diploma in IT at WelTec here in Wellington.

Technical Skills

Expand Skills List
Languages
  • JavaScript/ES6+
  • TypeScript
  • Python
  • Ruby
  • HTML5
  • CSS3
  • SASS/SCSS
  • SQL
Frameworks & Libraries
  • React
  • Next.js
  • React Router
  • Node.js
  • Express
  • Ruby on Rails
  • Flask
  • GSAP
Testing
  • Jest
  • React Testing Library
  • Cypress
  • Puppeteer
  • RSpec
  • Storybook
Data & Databases
  • PostgreSQL
  • MySQL
  • MongoDB
  • GraphQL
  • Prisma ORM
  • Sanity CMS
Infrastructure & DevOps
  • Git & GitHub
  • GitHub Actions
  • Jenkins
  • AWS
  • Heroku
  • Netlify
  • Docker
Practices
  • Web Accessibility (A11y)
  • Responsive Design
  • Component Architecture
  • Design Systems
  • Agile / Scrum
  • Code Review
  • Technical Writing
  • Mentoring & Pair Programming

Projects

Professional (Numeral Studio, 2025–present)

  • Numeral Studio Monorepo Template (2026)

    Codified the studio's existing best practice for new client projects into a shared monorepo template. Captured patterns the team had already proven across many client engagements and made them the default starting point. Cuts project initiation time by around 30%, saving days per kickoff for both the team and the client, and raises the baseline quality bar by giving every new project the same default stack and CI gates from day one. Next.js 15, React 19, TypeScript, Tailwind plus shadcn/ui, Vitest, Playwright, axe-core, Storybook, Turborepo.

  • Mobile experience platform

    Frontend work on a React/Next.js/TypeScript platform serving international markets. Converted images to WebP, added Korean and English localisation, and fixed iOS-specific search issues.

  • HR case-management product

    Full-stack work on a case management system for HR organisations. Built case routing, privacy controls, role-based access, and a Cypress end-to-end test suite.

  • Conference website platform

    Full-stack work on a conference website built with Next.js and Sanity CMS. Built shared components that cut code duplication by 70%.

  • Compliance Desktop App

    Front-end engineer on a React/Electron/TypeScript desktop application for commercial reporting, with a focus on accessible form components.

Habitual Genesis (Independent work & side projects, 2016–present)

Habitual Genesis is the umbrella I use for independent work: side projects, open-source contributions, freelance, and pro bono. I started it in 2016.

  • Price → Impact (2026)

    A Chrome extension that nudges you to donate to high-impact charities while you shop online. Two interventions: divert a planned purchase to a charity equivalent (anti-malaria bednets, deworming treatments, direct cash transfers), or round up the cart and donate the difference. TypeScript, MV3, GiveWell-derived data, MIT licensed. Companion web app and bookmarklet ship from the same Bun-workspaces monorepo.

  • nz-tech-events contributions (2026, ongoing)

    Spotted an opportunity to improve a community resource popular with the local tech community and contributed CI quality gates, structured-data SEO, shared model concerns, and test coverage for the password-reset and weekly-digest flows.

  • Read the Room Education (2026, ongoing)

    Pro bono website work for a non-profit focused on early-childhood education. Added Mailchimp newsletter signups and reworked the mobile layout. The mailing list grew 40% and mobile engagement went up 25%.

  • 'Slashtag' Website (2021)

    Built a mobile-first site for author Jon Cohn's book using Bootstrap, HTML5, CSS3, and JavaScript. Book sales went up 20% in the first month.

  • Mexic-Arte Museum (2017)

    Led a team of four to create a volunteer-maintained web presence for the museum during building renovations. Presented the recommended solution to the board of trustees.

Previous Roles (2014–2020)

  • Rewards Platform Re-architecture, WorkTango (2019–2020)

    Led a front-end team of three to move the Rewards platform from Rails to React. Customer engagement increased 15% and page load times dropped 30%.

  • Paywall Architecture, Condé Nast (2017–2019)

    Built a brand-agnostic paywall and React component library used across 26 media brands. Vanity Fair and Wired saw 100% year-over-year subscription growth. I also wrote a blog post on e2e testing the paywalls.

  • Bypass Mobile (2016) & Union Metrics (2014–2016)

    Earlier Rails work: a JSON-API licensing platform at Bypass Mobile, and a legacy codebase migration at Union Metrics that improved performance by 20%.

Community & Events

Organising and showing up at events is something I've done since before I was an engineer. A few highlights:

Open Source (Habitual Genesis)

Independent open-source work I do under the Habitual Genesis umbrella. Side projects, contributions, and community tools. The featured projects (price-to-impact, nz-tech-events contributions) are in the Habitual Genesis section above. Smaller bits and bobs below.