Contract Software Engineer

Virgin Atlantic & Holidays

I'm John, an award‑winning contract software engineer and front‑end web development specialist based in sunny overcast Brighton, UK.

I am a friendly and enthusiastic Principal Software Engineer and Technical Lead backed by over twenty‑three years of hands‑on experience.

I deliver bespoke websites, applications, and considered user experiences, pairing front‑end architecture with modern JavaScript (or TypeScript), React, HTML and CSS.

My portfolio is diverse; I work with global clients, solving real-world problems, including:

leading the modernisation of the online portfolio of one of Britain's largest airlines;
leading the headless replatforming of a much loved chain of restaurants, modernising its UK & Ireland web estate;
helping develop the online identity of Volvo's emerging premium EV brand;
... and optimising the online ordering system of Brighton's last independent milkman.

More about me

How I usually help

Planning a move to Next.js
For teams replacing an SPA, CMS front end, Gatsby build, or older Next.js architecture.
Something broke after launch
For teams who launched or migrated and then lost visibility, crawlability, or stable behaviour.
The live stack is unstable
For performance regressions, cache bugs, build failures, headless CMS issues, and Vercel debugging.

Featured Projects

Skip past clients

Previous Clients

John Lewis logo
The BBC logo
Gov.uk logo
HSBC logo
British Airways logo
eBay logo
Condé Nast Britain logo
Nintendo logo
Lotus Cars logo
Team GB logo
Marvel Comics logo
London Philharmonic Orchestra logo
Bosch (BSH Group) logo
Volkswagen logo
Cisco logo
Activision logo
London 2012 Olympics and Paralympics logo
Microsoft logo
Apple logo
Gatsby logo
Plex TV logo
LEGO logo
Selfridges logo
The World Economic Forum logo
Made by Many logo
AND Digital logo
IMG Licensing logo
Disney logo
Boohoo Group logo
Debenhams.com logo
The Rolling Stones logo
Wreel Agency logo
Polestar logo
MOSCOT logo
Virgin Atlantic logo
American Express logo
The Guide Dogs for the Blind Association logo
Style.com logo
Macmillan Education logo
Zara logo
Boeing logo
Valtech logo
McCann Manchester logo
Warwick Acoustics logo
Nando’s logo
Virgin Active logo

"
John Kavanagh is a fantastic developer with all the skills one would want in a lead developer. He's done a superb job on all tasks and has been a great resource within the company. Exceptionally knowledgeable, self‑motivated, and a great team player. I would certainly work with John again!"
Adam Millington Front‑end Developer
"
John Kavanagh is very sharp and detailed when it comes to handling complex HTML and CSS components. He has a very wide knowledge of Front‑End development and knows how to sort out any problem that arises. John was an essential part of the team, and I would be happy to work with him again in the future."
Isaac Goldfarb JavaScript Developer
"
John Kavanagh is an incredibly talented and efficient developer with great expertise in Gatsby and Contentful. He is incredibly personable and also always willing to share his knowledge. I also appreciated his ability to communicate openly and in a way that allowed me to find a way forward with him.
It was a pleasure to work with John and I would welcome another opportunity to work with him again!"
Clarisse Reyes Senior Client Success Manager
"
John Kavanagh is an exceptional programmer who consistently delivered high‑quality work at Selfridges. He possesses exceptional front‑end development skills and has a remarkable ability to tackle complex problems with creative and effective solutions.
What sets John apart is his strong work ethic and dedication to delivering results. He is a reliable and proactive team player, willing to go the extra mile to ensure project success. I was particularly impressed with his ability to resolve issues and make the explanations simple and succinct. He communicates effectively, collaborates seamlessly with team members, and approaches challenges with a positive and solution‑oriented mindset."
Gene Da Rocha Generative AI Engineer
"
John Kavanagh is a passionate and highly skilled developer with a wonderful ability to calmly concede downward business pressures whilst pragmatically delivering the project at hand.
John is never fazed by project management/requirement issues as are common in these environments, instead, he always finds a way to deliver value to both the end consumer and the business. It's not always easy to remain level‑headed and calm on high‑pressure projects but John's good nature and professionalism invariably remain infallible. It's an absolute pleasure working with him."
Menelik Williams Lead Full Stack Developer
"
It's been a pleasure to work with John Kavanagh in the web team at Nando’s. He's a top professional who has prided himself in bringing my designs to life with a high standard since day one. He has a great eye for detail with a clear understanding of user‑centric thinking and is always willing to give great suggestions from a technical standpoint.
I have also really appreciated his positive energy which gives a great lift to the team at every stand up. Any team would be lucky to work with him, as I have experienced myself!"
Edwin Yuen Senior Product Designer

Availability

I am currently leading a new digital transformation project. I expect to be available for my next challenge from September 2026.

View calendar

Latest Articles

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Want to find out more?

I've been delivering standout websites and applications for exceptional clients for over twenty-three years. Whether you've got a project underway or just an idea forming, drop me a line and let's see what we can build together.

Get in touch

Contract Software Engineer

I'm John, an award‑winning contract software engineer and front‑end web development specialist based in sunny overcast Brighton, UK.

How I usually help

Planning a move to Next.js

Something broke after launch

The live stack is unstable

Featured Projects

Lotus
Cars

LEGO

Polestar

Previous Clients

Availability

Sep

Oct

Nov

Dec

Latest Articles

Solving the LeetCode N‑Queens Problem

The AI Layoff Trap: When Local Efficiency Becomes Systemic Fragility

Using Angular Signals for Performance Optimisation

LeetCode: The 'Kth Smallest Element in a BST' Problem

Using RxJS for State Management in Angular

Backtracking Decision Trees: Solving 'Combination Sum'

GEO vs. SEO: Where They Overlap, and Where They Don't

Solving the 'Jump Game' Problem with Greedy Algorithms

Memoization in JavaScript: Optimising Function Calls

Dynamic Programming in LeetCode: Solving 'Coin Change'

Handling API Routes in Next.js: When to Use Server Actions vs. API Routes

LeetCode: Finding the Diameter of a Binary Tree

Want to find out more?

Contract Software Engineer

I'm John, an award‑winning contract software engineer and front‑end web development specialist based in sunny overcast Brighton, UK.

How I usually help

Planning a move to Next.js

Something broke after launch

The live stack is unstable

Featured Projects

Lotus Cars

LEGO

Polestar

Previous Clients

Availability

Sep

Oct

Nov

Dec

Latest Articles

Solving the LeetCode N‑Queens Problem

The AI Layoff Trap: When Local Efficiency Becomes Systemic Fragility

Using Angular Signals for Performance Optimisation

LeetCode: The 'Kth Smallest Element in a BST' Problem

Using RxJS for State Management in Angular

Backtracking Decision Trees: Solving 'Combination Sum'

GEO vs. SEO: Where They Overlap, and Where They Don't

Solving the 'Jump Game' Problem with Greedy Algorithms

Memoization in JavaScript: Optimising Function Calls

Dynamic Programming in LeetCode: Solving 'Coin Change'

Handling API Routes in Next.js: When to Use Server Actions vs. API Routes

LeetCode: Finding the Diameter of a Binary Tree

Want to find out more?

Lotus
Cars