Principal Full Stack JavaScript Engineer in Leeds

Type: Full-time, Permanent
Location: UK-based (flexible home, office, or hybrid working)

Office locations: Newcastle and Leeds
Hub locations: Edinburgh, Manchester, London

About the role

We’re growing our Engineering team to strengthen our ability to deliver world-class digital products for our clients. As a Principal Full Stack JavaScript Engineer, you’ll join a small, highly technical group tackling a complex transformation: breaking down a monolithic JavaScript platform into clearer, modern components. This is an individual contributor role for someone who thrives on problem‑solving, can ramp up quickly, and can collaborate confidently with other strong engineers. You’ll be hands‑on from day one, helping modernise architecture, improve maintainability, and set the foundations for future technology decisions, all while staying pragmatic and delivery‑focused.

What you’ll do

• Break down an existing monolithic system into well‑structured components and services.
• Work closely with senior client engineers, ask the right questions, and influence technical direction through evidence and collaboration.
• Support a move from Vercel‑hosted deployment towards a Google Cloud future, improving deployment and operational readiness.
• Contribute to authentication modernisation by integrating an identity platform rather than maintaining bespoke authentication.
• Deliver value quickly by rapidly understanding the domain, codebase, and priorities.

Who you are

• Strong full‑stack experience, including Node.js and API architecture.
• A pragmatic mindset: you care about quality, but you also deliver outcomes and keep momentum.
• Confident communicator who can hold their own in technical discussions with senior engineers.
• Comfortable working in small, flat teams with little hierarchy and lots of collaboration.

Nice to have

• Experience with Google Cloud (especially identity or auth‑related services).
• Experience with Vercel or modern web deployment platforms.
• Interest or experience in open source communities or open source strategy.
• Exposure to geospatial/GIS/mapping products or highly interactive map UIs.

Benefits

• 28 days of annual leave plus bank holidays
• 5 Impact Days per year to spend on L&D, volunteering or innovation
• Flexible working environment
• Enhanced parental policy
• Annual wellbeing budget + two days of wellbeing
• Mental health support
• Company‑supplied Apple Mac

Ready to apply?

Submit your application below. Please note that we’re unable to offer visa sponsorship for this role.