Senior Front End Developer

Senior Frontend Developer

Location: Portsmouth, Hampshire
Working Pattern: Office-based during probation, then minimum 3 days onsite per week
Salary: £60,000 - £70,000 plus benefits

An opportunity has arisen for an experienced Senior Frontend Developer to join an established technology business specialising in payment infrastructure, transaction processing and enterprise software solutions.

This is an excellent opportunity for a talented frontend engineer who enjoys building high-quality, scalable user interfaces and wants to take genuine ownership of frontend development across multiple products.

You'll be working on business-critical applications, including payment platforms, merchant-facing dashboards, secure checkout solutions and shared UI component libraries.

The business takes a modern, standards-based approach to frontend development, using TypeScript, JavaScript, Tailwind CSS and modern build tooling, rather than relying heavily on traditional frontend frameworks.

The Role

As a Senior Frontend Developer, you'll take responsibility for designing, developing and improving frontend applications used across the business.

Working closely with UI/UX designers and backend engineers, you'll deliver polished, secure and performant user interfaces.

Key responsibilities include:

• 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 onto modern component-based solutions.
• Work closely with UI/UX and backend development teams to deliver high-quality features.
• 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.

Essential experience:

• 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.

Desirable Experience

Any of the following would be advantageous:

• Experience with Lit or other Web Component technologies.
• Payment platforms, checkout systems or fintech applications.
• Accessibility standards, including WCAG and ARIA.
• Experience with PHP or Go backend applications.
• Data visualisation or rich-text editing functionality.
• Internationalisation and localisation.
• Contributions to open-source component libraries.

Please contact Tom Rayner on or email