Flagstone

About the Company

Flagstone – the cash deposit platform – gives savers everything they need to manage, protect, and nurture their cash.

With a single application, savers can spread their deposits across hundreds of accounts, maximise their interest, and keep their cash secure.

Our platform is available to UK individuals, businesses, and charities at www.flagstoneim.com.

We are available to international individuals, corporates, funds, and trusts at www.flagstoneim.com/international.

Listed Jobs

Company Name

Flagstone

Job Title

Senior Frontend Engineer

Job Description

Job title: Senior Frontend Engineer Role Summary: Lead the design, development, and delivery of high‑quality, scalable web applications in an Agile environment. Drive front‑end architecture, enforce best practices, and collaborate across cross‑functional teams to create resilient, performant products. Expectations: - 7+ years of front‑end development experience, demonstrating large‑scale project delivery. - Demonstrated leadership in shaping architecture and influencing engineering processes. - Proven ability to coach and guide junior developers. - Strong stakeholder communication and problem‑solving skills. Key Responsibilities: - Collaborate with product, UX, and backend teams to define and implement new features. - Design and deliver performant, maintainable UI components and pages. - Enforce coding standards, conduct code reviews, and maintain documentation. - Develop comprehensive test suites (unit, integration, E2E) using Jest, React Testing Library, Cypress. - Optimize front‑end performance (bundle size, rendering, resource loading). - Integrate and maintain design system components in Figma/Invision and Storybook. - Mentor junior engineers, providing technical guidance and best‑practice training. - Proactively suggest and implement process improvements and automation. - Mentor and expand the use of AI or tooling to boost engineering productivity. Required Skills: - Expert proficiency in JavaScript, CSS, and React.js. - Strong TypeScript knowledge (beneficial). - Experience with design systems (Figma, Invision) and Storybook. - Proficiency in front‑end testing frameworks (Jest, React Testing Library, Cypress). - Front‑end performance optimization techniques. - Familiarity with React Native (beneficial). - Excellent verbal and written communication. - Stakeholder management and collaboration. - Problem‑solving and analytical mindset. - Coaching and mentoring aptitude. Required Education & Certifications: - Bachelor’s degree in Computer Science, Software Engineering, or a related technical field (minimum). - Professional certifications in front‑end technologies (React, JavaScript) are a plus but not mandatory.

London, United kingdom

Hybrid

Senior

06-03-2026