Contract: Lead Full-Stack JavaScript Developer Contentful CMS – FTSE100 Investment Manager Day Rate: £685 via Umbrella Engagement Working Arrangement: Remote Our client is a leading UK investment company managing assets on behalf of over 1.8 million investors. Their website is a core part of their digital platform, and we're accelerating a migration to a headless CMS whilst building personalised, seamless client experiences across devices and channels. We're looking for a passionate Senior Full-Stack Engineer to join us on that journey. The Role: You'll build and maintain full-stack web applications, contribute to architectural decisions, and help drive engineering best practices across the team. You'll work in a cross-functional squad, mentor peers, and play a key role in shaping how we deliver digital experiences at scale. Responsibilities: Build and maintain full-stack applications using TypeScript, Next.js, Node.js and React Develop and maintain a design component library from Figma designs Write high-quality, secure, tested and performant code Own and improve automated testing strategies (unit, integration, e2e) Contribute to CI/CD and deployment processes Lead architectural planning and trade-off discussions Provide coaching and mentoring to peers Proactively support and maintain existing applications Experience & Knowledge: Strong hands-on experience with TypeScript, React, Next.js, Node.js Experience with AWS, Kubernetes, Docker and Lambda functions Experience working with Contentful CMS (content modelling, delivery APIs) Familiarity with infrastructure as code Testing experience with Jest and Playwright Understanding of RESTful APIs and microservices principles Comfortable working in an Agile, DevOps environment Proficient with Git and CI/CD pipelines (GitLab preferred) Solid knowledge of HTML, CSS (Tailwind/SCSS) and web accessibility Desirable: Experience with MarTech tools (A/B testing, analytics, personalisation, tag management) Experience deploying Next.js applications via Netlify