I build products,
end to end.

Senior full-stack engineer with 10+ years shipping production software. From database schema to production UI, for brands like Primark and SuperDry. Originally a mechanical engineer and fusion energy researcher.

See my work
Me rescuing a tortoise from a road in Croatia

About me

I studied mechanical engineering at Cardiff, then did a master's in fusion energy at York. Somewhere along the way I taught myself to code, discovered I was good at it, and never looked back.

I've spent the last 11 years at one company, but that single tenure hides a lot of range: 6+ greenfield products built from scratch, a company rebrand and pivot, and clients ranging from Primark to Triumph Motorcycles. I've gone from junior developer to senior architect, and I now own technical direction for major systems in a small, fast-moving team.

Based in Budapest. When I'm not coding I'm usually climbing, caving, or playing guitar.

Experience

CORE (UK) Ltd → TariffTel · Trade compliance software for global brands

2022 – Present
Senior Developer / Architect
TariffTel 2.0
.NET 8/10 · Angular 19 · Clean Architecture · CQRS · SignalR · Azure

Ground-up rewrite of a 10+ year legacy platform. The old system was a mix of ASP.NET WebForms, WinForms, and millions of lines of business logic buried in SQL stored procedures across 10 separate database repositories. Designed the new architecture from scratch and built the full system in under a year with a small team. Real-time messaging via SignalR, enterprise SSO through Microsoft Entra ID, and shared NPM libraries enabling consistent logic across multiple frontends.

Master Data Management System
.NET 10 · Angular 19 · Tailwind · Dapper

New system built on .NET 10 with a custom CQRS dispatcher (replacing MediatR), Dapper for performance-critical queries, and a Tailwind-based Angular UI.

2017 – 2022
Developer
Customs Connect
Azure Functions · .NET · Serverless

Customs declaration software built for Primark. Rebuilt v2 as a fully serverless Azure Functions application, integrating with classification and supply chain systems to automate the declaration process.

LEAF
MVC · Azure Functions · Sustainability

Sustainability reporting platform tracking fibre origins for the SCAP scheme. Built from scratch with a small team. Adopted by Primark and being evaluated by SuperDry before their restructure.

TariffTel Essentials & Premium
Angular · .NET · B2C / B2B

Built TariffTel Essentials, a B2C customs classification web app. Later built TariffTel Premium (the B2B version) single-handedly, which laid the architectural groundwork for the eventual TariffTel 2.0 rewrite.

2014 – 2017
Junior Developer
Supply Chain & Classification Software
Primark · SuperDry · Triumph Motorcycles

Production supply chain and classification systems serving major UK and international brands. First greenfield project: sustainability reporting for Primark's SCAP fibre-origin programme.

Tech

What I reach for most. I pick up new tools fast.

.NET
.NET
C#
C#
TypeScript
TypeScript
Angular
Angular
React
React
Python
Python
Node.js
Node.js
Azure
Azure
Docker
Docker
PostgreSQL
PostgreSQL
SQL Server
SQL Server

Side Projects

Things I build outside of work to explore new stacks and ideas.

DevSync
Next.js 16 · PostgreSQL · Prisma · NextAuth

Multi-tenant snippet manager with team collaboration, RBAC, full-text search, GitHub OAuth, email invitations, and subscription tiers. Dockerized and production-ready.

CodeMop
Python · FastAPI · PostgreSQL

AI code review tool. Hooks into GitHub PRs via webhooks and suggests improvements automatically.

EV Route Optimizer
Node.js · React 19 · Leaflet

Full-stack EV journey planner. Express backend with GraphHopper and OpenChargeMap; React frontend with interactive maps.

EV Fleet Platform
.NET 8 · Python · Google OR-Tools

Polyglot microservices. .NET fleet management API paired with a Python/Flask optimization engine for vehicle routing.

What I Bring

How colleagues and clients describe working with me.

Ship complete products

Database to UI, auth to deployment, working solo or in a team. I own the full stack and deliver working software.

Design systems that last

Clean Architecture, CQRS, modular boundaries, tested and documented. I think about what happens in two years, not just two sprints.

Pick up anything

C#, TypeScript, Python, React, Node. I'm not attached to a stack. Whatever the problem needs, I'll learn it and ship it.

Move fast, don't cut corners

Docker, CI/CD, automated tests, and structured logging from day one. Speed and quality aren't a trade-off.

Get in touch

Have a project or question? I'd like to hear from you.

Or email me directly: greg@kempgt.com