Principal Software Engineer & Technical Lead

Handson engineering leadership for complex digital transformation programmes. I help product and engineering teams turn fragile legacy web estates into faster, more maintainable platforms that are easier to scale, govern, and improve.

I'm John, an awardwinning software engineering specialist based in sunny Brighton, UK.

I am an enthusiastic principal software engineer and technical leader with over twentythree years of handson experience.

I help teams and clients design, build and improve websites, applications and web platforms, pairing architecture, delivery judgement and handson TypeScript, React, HTML, and CSS.

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

More about me

Featured Case Studies

  1. Featured case study

    Virgin Atlantic
    & Holidays

    Lead engineer on this massive replatforming project, unifying twelve disparate applications under a new headless architecture with React and Next.js.

    Screenshot of the Virgin Atlantic & Holidays website; part of John Kavanagh's selected project work.
  2. Featured case study

    John Lewis
    & Partners

    Senior developer as part of team 'Findability'. Led the digital implementation of the 'John Lewis & Partners' rebrand alongside new feature development, user journey optimisation, and performance improvements.

    Screenshot of the John Lewis website; part of John Kavanagh's selected project work.
  3. Featured case study

    HSBC Corporate
    Banking

    Lead UI development for a set of HSBC digital transformation projects, including a React, TypeScript, Node.js, and AEM rebuild of commercial banking applications.

    Screenshot of the HSBC Corporate Banking website; part of John Kavanagh's selected project work.
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Previous Clients

Availability

I am currently leading a global digital transformation engagement, with limited availability until late 2026. Short diagnostics or urgent work may be possible sooner.

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Want to find out more?

If you need senior handson support with a complex React or Next.js platform, migration, performance issue, or technical SEO problem, send me the context and I'll tell you where I can help.