Senior Front-End Developer

• Design, develop and maintain modern frontend applications using TypeScript and JavaScript
• Build and enhance reusable Web Components and shared UI component libraries
• Develop merchant-facing applications, dashboards and secure payment interfaces
• Maintain and improve browser-based payment integrations and checkout functionality
• Champion frontend performance, accessibility, usability and cross-browser compatibility
• Modernise legacy frontend applications and migrate older interfaces to modern component-based solutions
• Work with UI/UX designers and backend engineers to deliver high-quality features and user interfaces
• Write clean, maintainable code supported by automated testing
• Contribute to frontend architecture, technical decisions and development standards
• Mentor other developers and promote engineering best practices

Technologies:

• Backend
• CSS
• Frontend
• JavaScript
• PHP
• Playwright
• SCSS
• Security
• TypeScript
• Web
• UX UI Design

• Significant commercial experience in frontend software development
• Excellent TypeScript and modern JavaScript skills
• Strong knowledge of HTML, CSS and browser technologies
• Experience with the DOM, browser events, Shadow DOM and Custom Elements
• Strong CSS skills, ideally including Tailwind CSS and SCSS
• Experience developing reusable UI components, component libraries or design systems
• Familiarity with modern frontend build tools such as Vite, Rollup or esbuild
• Experience with automated frontend testing tools such as Playwright, Vitest or similar
• Good understanding of web security, accessibility and frontend performance
• Experience taking ownership of complex production applications
• Experience with Lit or other Web Component technologies is advantageous
• Experience with payment platforms, checkout systems or fintech applications is advantageous
• Knowledge of accessibility standards, including WCAG and ARIA, is advantageous
• Experience with PHP or Go backend applications is advantageous
• Experience with data visualisation or rich-text editing functionality is advantageous
• Experience with internationalisation and localisation is advantageous
• Contributions to open-source component libraries are advantageous

We are seeking a Senior Frontend Developer to join an established technology business specialising in payment infrastructure, transaction processing and enterprise software. Our products include business-critical payment platforms, merchant-facing dashboards, secure checkout solutions and shared UI component libraries. We take a modern, standards-based approach using TypeScript, JavaScript, Tailwind CSS and modern build tooling. The role is based in Portsmouth, Hampshire, with office attendance during probation and a minimum of three onsite days per week thereafter. The salary is £60,000-£70,000 plus benefits. Spectrum IT Recruitment (South) Limited is acting as an Employment Agency in relation to this vacancy.