Portfolio | James Calmus
James Calmus

Portfolio

I build high-impact frontend systems that drive real results.

Senior frontend lead: I care about product outcomes, fast reliable UIs, and teams that know what they are optimising for.

  • £5m+ revenue impact
  • 1.5m users
  • 96% performance improvement
View my work

Featured work

Platforms at real scale, infrastructure that does not cost the earth, and a few builds that had to go live almost immediately.

Insurance policy paperwork with magnifying glass, model car, and cash on a white surface

Platform

Scaling a high-conversion insurance platform

£5m+ revenue impact from the conversion and platform work

Problem

The quote journey and the wider frontend were slowing growth. Conversion was leaking, patterns were inconsistent, and performance debt had stacked up across a large surface with lots of teams involved.

Approach

I led frontend strategy for a group of twelve engineers, rebuilt the quote journey around clear conversion targets, and put a GraphQL layer in so product teams could ship without getting in each other’s way.

Outcome

The business attributed £5m+ to the redesign, the GraphQL stack now serves about 1.5m users, and we landed roughly a 96% performance gain. Pages got faster, ownership got clearer, and delivery lined up with the roadmap again.

  • £5m+ Revenue impact
  • 1.5m Users served
  • 96% Performance gain
  • React
  • TypeScript
  • GraphQL
  • Performance
  • Design systems
  • Team leadership
Laptop screen showing the WordPress.com homepage

CMS / Performance

Replacing WordPress with a zero-cost, high-performance platform

Fragile, expensive hosting replaced with something fast, resilient, and near-zero cost

Problem

A client whose website I was redesigning had a WordPress site that was costly to run and painful when it broke. Editors needed to publish on their own, and the site still had to stay quick when campaigns drove traffic.

Approach

I designed and built a custom CMS on Next.js: Supabase for content, Upstash where rate limits mattered, Vercel for deploys. Edge caching first, then editor workflows so marketing wasn’t blocked.

Outcome

Hosting spend effectively disappeared, non-technical editors ship content themselves, and the stack still feels fast and stable at the edge.

  • Near zero Hosting
  • Edge-first Stack
  • Self-serve Editors
  • Next.js
  • Supabase
  • Upstash
  • Vercel
  • TypeScript
Gamban4Greyhounds campaign visual

Campaign

Turning awareness into political action in 48 hours

Designed and launched in two days

Problem

The story had to push people from reading to doing something, and the write-to-your-MP flow had to feel serious and trustworthy, not like a gimmick.

Approach

Scroll-led storytelling, a focused MP journey, and UK Parliament data over GraphQL so each message had the right context behind it.

Outcome

We shipped end to end in 48 hours: UX aimed at action, data that held up in production, and a path tuned for conversion.

  • 48 hrs Time to launch
  • MP action Focus
  • Parliament API Data
  • Next.js
  • GraphQL
  • Campaign UX
  • Storytelling
Low-light photograph of poker chips and playing cards on a green felt table

Launch

Creating a credible digital presence for a new charity

Went from a placeholder site to a proper launch platform

Problem

A brand-new charity needed to look established straight away: a clear story, design that felt trustworthy, and a way to update the site without a full-time engineer.

Approach

I did the full UX in Figma, then built a CMS-like structure on a modern site builder and wired in Mailchimp so comms could sit next to the site.

Outcome

They launched looking credible, with workflows marketing could run themselves instead of waiting on developers for every change.

  • Figma to live UX
  • Self-serve Content
  • Mailchimp Email
  • Figma
  • Site builder
  • Mailchimp
  • Content design

Experience

Where I have actually shipped work, in one line each. Not a CV.

  1. Policy Expert

    Leading frontend strategy and delivering measurable business impact

  2. Digital Theatre

    Built a modern streaming platform with Next.js and AWS

  3. Orvista Health

    Architected a platform for the NHS with role-based systems

  4. Wilder Digital

    Delivered campaign and social platforms for clients

Capabilities

Engineering, product craft, and leadership, plus the platforms I use when they are the right fit for the brief.

Engineering

  • React
  • Next.js
  • Angular
  • TypeScript
  • Node.js
  • GraphQL
  • AWS

Product & UX

  • Design systems
  • Performance optimisation
  • Conversion-focused UX

Leadership

  • Tech strategy
  • Mentoring
  • Team leadership
  • Architecture

Platforms & tooling

  • Supabase
  • Wix
  • names.co.uk
  • Mailchimp
  • GTM
  • Webflow
  • Framer

Let’s build something exceptional.

Work with me