Principal Full Stack JavaScript Engineer - Contract

hedgehog lab; Greater London; Hybrid; GBP 125,000 - 150,000; Full time

Job summary

A digital product consultancy is seeking a Principal Full Stack JavaScript Engineer to lead a technical team in transforming a monolithic platform into modern components. You will engage in hands-on engineering, focusing on architecture and collaboration with senior clients. Ideal candidates will have deep expertise in JavaScript, strong full-stack skills, and a pragmatic mindset. This position offers flexible home, office, or hybrid working in various UK locations, including London.

Qualifications

• Deep expertise in JavaScript, with TypeScript as a plus.
• Strong full-stack experience, including Node.js and API architecture.
• Confident communicator capable of engaging in technical discussions.

Responsibilities

• Lead full-stack engineering across a JavaScript platform.
• Break down a monolithic system into structured components.
• Work closely with senior client engineers to influence technical direction.

Skills

JavaScript

Node.js

API architecture

TypeScript

Google Cloud

Job description

Type : Full-time, Contract (outside IR35)

Location : UK-based (flexible home, office, or hybrid working)

Office locations : Newcastle and Leeds

Hub locations : Edinburgh, Manchester, London

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 very 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

• Lead (hands‑on) full‑stack engineering across a JavaScript platform, with a strong focus on architecture and problem‑solving.
• 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 quickly understanding the domain, code‑base, and priorities.

Who is hedgehog lab

hedgehog lab is a digital product consultancy with 20 years of experience. Based in Northern England, we help global brands craft better digital experiences through technical excellence and human‑first collaboration.

What we’re looking for

• Deep expertise in JavaScript (TypeScript a plus).
• 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.

Ready to apply?

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