BENJAMIN CEGLOWSKI
ceglow.ski linkedin.com/in/benceglowski
Principal Software Engineer
London, United Kingdom
Principal Full Stack Engineer with 20+ years' experience building high-performance web applications. I specialize in React ecosystems, design system architecture, and leading cross-functional engineering teams to deliver products used by millions.
Passionate about the intersection of engineering excellence and design craft. I believe great interfaces are invisible — they get out of the way and let people accomplish what they came to do.
Currently focused on performance at scale, developer experience & accessibility.
Experience
HARMONIC SECURITY
2025 — Present
Principal UI Engineer
— Principal UI Engineer at a fast-paced AI startup, responsible for delivering the core product interface end-to-end.
— Architect and ship high-quality React applications at speed using React and Vite, balancing rapid iteration with production-grade robustness and performance.
— Drove significant frontend performance improvements, reducing load times and runtime overhead while maintaining a refined, responsive user experience.
— Instrumental in streamlining developer experience (DX), introducing tooling, build optimisations, and workflow improvements that accelerated development velocity across the team.
— Reduced product friction through thoughtful UI architecture, interaction design, and systematic refactoring, enabling faster feature delivery with fewer regressions.
— Established frontend standards and patterns that improved maintainability, consistency, and long-term scalability in a high-growth environment.
DELIBERATE SOFTWARE LTD
2021 — 2025
Lead Consultant Software Engineer
— Design and deliver end-to-end web solutions for clients across e-commerce and fintech. Principal-level technical leadership, mentoring, architecture, and strategic guidance.
— Perfect Moment — Full production and upkeep of e-commerce platform: TypeScript, Next.js, GraphQL, Clojure, Contentful, Commercetools.
— Moo — Full-stack services for checkout and back-end PIM integration: TypeScript, Next.js, AWS, Salsify, Commercetools.
— Ebury — Trading application: TypeScript, Next.js, Python, PostgreSQL, AWS; hands-on mentorship and technical direction.
CRAFTING THE INTERNET LTD
2018 — 2021
Founder · Director · Technical Lead
— Software engineering and technical leadership across transport, education, energy, and compliance. End-to-end architecture, mentorship, and best practices.
— Riskbase — Lead engineer for mobile risk-assessment app (TypeScript, React Native). Shell Agile Hub — Logistics tracking platform (TypeScript, React, GraphQL, Node.js, Azure). EF — Scheduling platform for language tuition (TypeScript, React, MobX, Go). Trainline — International rail travel features (TypeScript, React, Redux, Node.js, C#).
ONEFINESTAY
2016 — 2018
Senior Full Stack Engineer
— Drove development of a new statically rendered React application architecture for the main platform.
— Advised product, SEO, and CRO teams; led migration from costly SaaS tools to in-house replacements.
— Full-stack: JavaScript, React, GraphQL, Node.js, Python, Django, AWS, Jest.
PHUSE.CA
2014 — 2016
Head of Engineering
— Led distributed, asynchronous engineering team delivering bespoke web consultancy.
— Oversaw project delivery and code quality across JavaScript, PHP, React, Node.js, Angular, Vue.js, MySQL.
— Implemented company-wide engineering standards and best practices; architected full-cycle applications.
THE BIO AGENCY
2012 — 2013
Senior Software Engineer · UI Team Lead
— Led front-end team developing web platform for Yell Group. Technical leadership, mentorship, training.
— JavaScript, HTML, CSS, PHP, MongoDB, Backbone, Ember (LAMP).
SHINE MARKETING
2011 — 2012
Web Software Engineer
— Developed end-to-end retail e-commerce websites for a London-based boutique consultancy.
— Delivered full-stack solutions using PHP, MySQL, JavaScript, HTML, CSS, and jQuery.
FREELANCE
2006 — 2011
Web Software Engineer
— Delivered web design and development services for several Durban and London-based consultancies.
— Provided full-stack engineering across JavaScript, PHP, MySQL, Apache, and MongoDB, creating performant and maintainable digital solutions for clients.
Technical Skills
Languages
TypeScript
JavaScript
HTML5
CSS3
GraphQL
SQL
Frameworks
React
Next.js
Remix
Node.js
Astro
Svelte
Tools
Webpack
Vite
Figma
Git
Docker
CI/CD
Practices
Design Systems
A11y
Perf Optimization
TDD
Code Review
Mentorship
Education
Durban University of Technology
Bachelor of Technology (Distinction)
2006 — 2010
Kearsney College
Matric (IEB Higher Grade)
2005