Senior Front End Developer (Remote, UK)

IQ Integrity builds and delivers ONE, an Asset Integrity Management platform. ONE helps oil, gas and wind operators extend asset life.

You’ll work across a large, mature codebase that we’re actively modernising: a server-rendered, multi-page core. This is real enterprise software — used daily, long-lived, and held to a high standard for maintainability.

We’re looking for a senior front-end engineer who is excellent at the fundamentals — not just fluent in a framework, but someone who understands the browser, writes code built to last, and can move confidently through a large, established codebase. You’ll help shape our shift to React and a shared design system while keeping the existing platform solid and maintainable.

What you’ll do

• Build and improve features across our platform, from the server-rendered core to newer React/TypeScript areas
• Develop and maintain shared, reusable components and design tokens so the UI stays consistent at scale
• Work with complex, data-heavy interfaces — large grids, dashboards and interactive components — with an eye on performance
• Read, debug and safely refactor long-lived legacy code, leaving it better than you found it
• Set the bar on code quality, testing and front-end practice, and help mentor other developers
• Build testable UIs — stable test hooks (e.g. data-testid) and predictable component states — and work with QA to keep our automated end-to-end tests (Selenium/Jenkins) reliable

Must-have

• Expert vanilla JavaScript and DOM fundamentals — event handling, memory, performance profiling and debugging (deep language skill, not just framework experience)
• Strong CSS at scale — design tokens and maintaining a shared component/design system
• Production React with solid JavaScript/TypeScript
• Comfortable reading and debugging large legacy codebases
• A track record building enterprise applications, writing new code to a maintainable, long-lived standard
• Works with testing as standard — unit (Jest/Vitest, React Testing Library) and some end-to-end (Playwright or Cypress)
• Solid version control — Git or SVN (we use SVN; Git experience transfers directly)
• Able to mentor and raise standards across a team

Strongly desirable

• Data-grid experience — AG Grid ideal
• Experience maintaining a server-rendered, multi-page application
• Storybook for component development
• Awareness of accessibility (WCAG) in enterprise UI
• Experience making complex UIs (data grids, rich widgets)testable for automated end-to-end tests

What we offer

• Fully remote within the UK — work from anywhere in the UK
• Competitive salary, dependent on experience
• Company pension
• Employee stock ownership plan
• Cycle to work scheme
• Casual dress
• The chance to modernise a mature, widely-used enterprise platform, working alongside a small, experienced team

Eligibility: This role is open only to candidates currently based in the UK who hold the right to work in the UK. We cannot offer visa sponsorship, so applications that would require it will be declined.

How to Apply
We hire directly. Apply through the Indeed portal with your CV and a short cover note. Applications are reviewed on a rolling basis. In your cover note, please tell us:

• your experience within SaaS or web-application development
• why you feel you’d be a good fit for the role

No agencies: We’re a small independent company and hire directly — we don’t work with recruitment agencies for this role, so please, no agency approaches.

Pay: £39,000.00-£50,000.00 per year

Benefits:

• Casual dress
• Cycle to work scheme
• Employee stock purchase plan

Work Location: Remote