Front End Developer - SC Cleared - Outside IR35

iO Associates; City Of London; On-site; GBP 80,000 - 100,000; Full time

Job summary

A leading UK Defence tech innovator is seeking a Senior Frontend Engineer to lead user-facing experiences for a generative AI chat platform. The ideal candidate will have over 5 years of frontend development experience with React and TypeScript. You will collaborate with various teams to build performant, scalable, and accessible applications. This role offers a competitive rate and a hands-on opportunity to influence product direction.

Qualifications

• 5+ years of frontend development experience.
• Strong knowledge of React and TypeScript in production.
• Ability to architect complex single-page applications.

Responsibilities

• Own user-facing experiences end-to-end.
• Architect and deliver performant, scalable applications.
• Partner with backend and AI teams to impact product direction.

Skills

React & TypeScript

Architecting complex SPAs

State management (Zustand, TanStack Query)

Vite

Git workflows

API integration

Real-time features (WebSockets)

Performance optimisation

Responsive design

Authentication flows (Azure MSAL/OAuth2)

Communication and mentoring

Tools

Docker

GitHub Actions

Job description

Location: London
Clearance: Active SC or DV required
Rate: Competitive / Negotiable (Outside IR35)
Duration: 6 Months (scope to extend)

Overview

I'm looking for a Senior Frontend Engineer to join a fast-growing UK Defence tech innovator building a generative AI chat platform. You'll be owning the user-facing experiences end-to-end, architecting and delivering performant, scalable, and accessible applications that make advanced AI capabilities intuitive and engaging for end users.

This is a hands-on role where you'll partner with backend and AI teams, have a direct impact on product direction, and set the standard for modern frontend practices.

Essential Experience

• 5+ years of frontend development with React & TypeScript in production
• Proven track record architecting complex SPAs with modern routing (React Router v7)
• Strong knowledge of state management (Zustand, TanStack Query)
• Skilled in Vite, pnpm, and Git workflows
• Experience integrating with APIs (OpenAPI / Orval) and real-time features (WebSockets, streaming data)
• Deep understanding of browser APIs, performance optimisation, and responsive design
• Strong experience with authentication flows (Azure MSAL/OAuth2)
• Excellent communicator, able to mentor and influence frontend standards

Nice to Have

• Experience with AI SDK React and streaming endpoint integrations
• Familiarity with Tailwind CSS v4 and Shadcn/ui component systems
• Knowledge of CI/CD pipelines (GitHub Actions) and containerisation (Docker)
• AWS deployment experience (CloudFront/S3, caching/CDN strategies)
• Exposure to accessibility standards (WCAG 2.1 AA) and testing frameworks (unit/integration/E2E)
• Interest in security best practices (CSP headers, XSS prevention, secure API comms)

If this is something of interest, feel free to apply or email me at