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    Hi, I’m Matt.

    Lead Developer · platform engineering × AI-native architecture · real-time UIs · calisthenics as the lens.

    Matthew Castrillon-Madrigal

    I'm Matt, a Lead Developer. I currently lead front-end work at a fintech building real-time crypto trading interfaces — the kind of UI where a frame dropped is a price missed. Before that I was UI Lead Developer at Sky, where I led the front end of a low-code network automation platform, built a network-graph component library and chaired a cross-department UI community.

    I care about platforms that make the right thing the easy thing, interfaces that stay fast under pressure, and testing that gives teams confidence rather than ceremony. Lately I'm especially interested in what platform engineering looks like when AI agents are users of the platform too.

    Outside work I train calisthenics — mostly handstands — and I've found the same ideas everywhere: progressive overload is incremental migration, a deload is a tech-debt sprint, and a skill tree is just a learning path you can see. This site is where I write those connections down.

    I studied Computer Science at the University of Kent, graduating with a First and specialising in AI and machine learning. I live in the terminal (Neovim, tmux) and build my own tools when I can.

    Experience

    1. 2026 – present

      Lead Developer · Haruko

      Lead developer for high-performance, low-latency trading platforms at a fintech building real-time crypto trading UIs.

      • Real-time trading execution, click-to-trade and RFQ workflows, and modernised live quote pricing.
      • Market visualisations that hold 60fps under a constant stream of updates.
      • Turning client requirements into designs and architecture, and delivering at pace without compromising quality or latency.
      • React
      • TypeScript
      • Java
    2. 2023 – 2025

      UI Lead Developer · Sky

      Led UI development for a scalable, secure low-code network automation platform serving multiple Sky teams and external partners.

      • Planned, designed and delivered a React network-graph component library that gives clients clear insight into their networks.
      • Chaired UI/UX across Telecoms Management: regular cross-department workshops, aligned tooling and a consistent, accessible UX.
      • Drove a testing strategy overhaul, adopting Playwright for end-to-end testing across departments.
      • Directed and mentored UI developers, roadmapped projects and worked closely with network engineers and product.
      • High availability and security: OpenAPI contracts, Python endpoints, API gateway configuration and security scans in merge pipelines.
      • Next.js
      • TypeScript
      • Tailwind
      • Zustand
      • React Query
      • Playwright
      • Storybook
      • Vitest
    3. 2021 – 2023

      Mid-Senior HTML5 TV Developer · Accedo

      Delivered the My5 (Channel 5) app across connected-TV platforms.

      • Memory and performance optimisation for low-powered TV devices.
      • A full rebrand of the My5 connected-TV application and major performance improvements.
      • Started a weekly knowledge-sharing culture, introduced pair programming and mentored new joiners.
      • CI/CD pipelines in Jenkins; features across auth, playback and search.
      • React
      • Redux
      • TypeScript
      • JavaScript
    4. 2019 – 2021

      Full Stack Developer · Elanco

      Part of the global web digital team transforming 80+ active sites.

      • Lead developer on a CMS migration, coordinating a dozen-plus onshore and offshore developers.
      • TypeScript and GraphQL tooling for media and content migrations.
      • Established modern content sites with Next.js and Gatsby and shaped enterprise web standards.
      • TypeScript
      • GraphQL
      • Next.js
      • Gatsby
      • Headless CMS

    Education

    BSc Computer Science — First Class

    University of Kent · Specialised in artificial intelligence and machine learning.