Senior UI Developer

📍 Job Overview

Job Title: Senior UI Developer

Company: Trustonic

Location: Winnersh, England, United Kingdom

Job Type: Full-time

Category: Frontend Engineering / UI Development

Date Posted: 2026-05-07T17:37:22.838

Experience Level: Senior (5-10 years)

Remote Status: Hybrid

🚀 Role Summary

• Lead the design, development, and maintenance of a modern, React 18-based operator web portal for a next-generation telecoms platform.

• Develop and manage a scalable component library using Ant Design, ensuring UI consistency and reusability across a complex SaaS platform.

• Integrate with secure AWS AppSync GraphQL APIs and Cognito authentication flows to deliver real-time, secure user experiences.

• Implement efficient data-fetching and state management patterns (e.g., React Query, Zustand) for real-time device data and manage application performance through optimization techniques.

📝 Enhancement Note: This role is positioned as a Senior UI Developer, indicating a need for significant hands-on development expertise coupled with the ability to take ownership and provide technical leadership within the frontend domain. The focus on a "next-generation telecoms platform" and "device lifecycle management at scale" suggests a critical role in shaping customer-facing interfaces for a core business product.

📈 Primary Responsibilities

• Architect, build, and maintain responsive, intuitive, and high-performance user interfaces for the operator web portal using React 18.

• Develop and champion a reusable component library with Ant Design, ensuring adherence to design guidelines and promoting frontend best practices.

• Integrate seamlessly with backend services, specifically AWS AppSync GraphQL APIs and Cognito for authentication, to enable secure and real-time data interactions.

• Implement robust state management solutions (e.g., React Query, Zustand) to efficiently handle complex application states and real-time data streams.

• Drive frontend performance optimization through code-splitting, lazy loading, caching strategies, and other advanced techniques to ensure a fast and scalable user experience.

• Collaborate closely with backend engineers on API design, schema evolution, and data modeling to facilitate efficient frontend development.

• Partner with product and UX teams to translate sophisticated platform capabilities and user needs into elegant and usable interfaces.

• Write comprehensive unit and integration tests using Jest and React Testing Library to ensure code quality, reliability, and maintainability.

• Conduct thorough code reviews, provide constructive feedback, and contribute to the continuous improvement of frontend development processes and standards.

• Champion user experience best practices, ensuring applications meet high standards for responsiveness, cross-browser compatibility, and accessibility (WCAG).

📝 Enhancement Note: The responsibilities highlight a blend of core development, technical leadership, and cross-functional collaboration. The emphasis on "device lifecycle management at scale" and "complex SaaS platform" implies a need for robust, scalable, and secure frontend solutions. The requirement to "own state & data management" and "drive frontend performance" points towards a senior-level expectation for deep technical understanding and proactive problem-solving.

🎓 Skills & Qualifications

Education:

• A degree in computer science, software engineering, or a related field, or equivalent practical experience.

Experience:

• Strong commercial experience in building and deploying production-grade React applications.

• Proven track record of working with GraphQL APIs (e.g., AWS AppSync, Apollo, Relay) and understanding API design principles.

• Hands-on experience implementing authentication and authorization flows, such as AWS Cognito, OAuth2, or OIDC.

• Significant experience utilizing TypeScript in a React codebase, including advanced typing patterns and generics for scalable solutions.

• Demonstrated experience with modern frontend build tools and workflows, such as Vite or equivalent.

• Experience with state management libraries like React Query, Zustand, Redux, or similar, and understanding their application in complex scenarios.

• Strong proficiency in CSS/SCSS, with a deep understanding of responsive design principles (flexbox, grid) and cross-browser compatibility.

Required Skills:

• Deep understanding of React 18 features, including Hooks, Context API, performance optimization techniques, and component lifecycle management.

• Expertise in TypeScript, including writing robust, maintainable, and scalable code.

• Proficiency in consuming and interacting with GraphQL APIs.

• Experience with component-based architecture and design systems, specifically Ant Design or similar libraries.

• Ability to implement efficient data fetching and state management strategies for real-time applications.

• Strong problem-solving skills and a methodical approach to debugging and performance tuning.

• Excellent communication and collaboration skills, with the ability to work effectively in a cross-functional team environment.

Preferred Skills:

• Experience with multi-tenant SaaS platforms and understanding the complexities of scaling applications for multiple clients.

• Familiarity with a broader range of AWS services relevant to frontend development, such as S3, CloudFront, Lambda, and CloudWatch.

• Knowledge of web performance optimization techniques beyond basic code-splitting and lazy loading.

• Awareness and practical application of web accessibility standards (WCAG) to ensure inclusive design.

• Experience working with design systems and contributing to UX best practices.

• Understanding of CI/CD pipelines for frontend applications.

📝 Enhancement Note: The qualifications emphasize deep expertise in React and TypeScript, crucial for building complex, modern web applications. The inclusion of GraphQL, AWS services, and state management libraries points to the need for a developer who can handle intricate integrations and data flows. The "Nice to Have" section clearly indicates areas where additional experience would make a candidate stand out, particularly in SaaS environments and broader cloud infrastructure knowledge.

📊 Process & Systems Portfolio Requirements

Portfolio Essentials:

• Demonstrations of complex, interactive user interfaces built with React 18, showcasing responsive design and intuitive navigation.

• Examples of reusable component libraries or design system contributions, highlighting consistency and maintainability.

• Case studies or code samples illustrating integration with GraphQL APIs, including data fetching, state management, and error handling.

• Projects that showcase experience with authentication/authorization flows, demonstrating secure user session management.

• Evidence of performance optimization techniques applied to frontend applications, with measurable results if possible.

Process Documentation:

• Documentation or examples of unit and integration tests written for React components and application logic, demonstrating a commitment to code quality.

• Examples of how you've approached code reviews, including feedback provided and received, to foster a culture of continuous improvement.

• Any personal documentation on frontend architecture patterns, state management strategies, or component library development workflows.

• Proof of collaboration on projects, potentially through contributions to shared documentation, wikis, or project management tools.

📝 Enhancement Note: For a Senior UI Developer role, a portfolio is critical. It should not only showcase technical skills but also the developer's ability to design, implement, and maintain robust, scalable frontend solutions. Emphasis should be placed on projects demonstrating complex interactions, performance, and integration with backend services. The "Process Documentation" aspect is to gauge the candidate's understanding and engagement with development methodologies and quality assurance.

💵 Compensation & Benefits

Salary Range:

The salary for this Senior UI Developer role in Winnersh, UK, with 5-10 years of experience, is estimated to be between £60,000 and £85,000 per annum. This range is based on industry benchmarks for senior frontend developers in the UK tech sector, considering the specified location and the advanced technical requirements of the role.

Benefits:

• Competitive Compensation: A base salary reflecting expertise and impact, alongside a bonus scheme to acknowledge company success.

• Financial Security & Wellbeing: Immediate participation in the company pension scheme, comprehensive private medical insurance for the employee and family from day one, and robust income protection and life insurance policies.

• Flexibility & Work-Life Balance: Options for remote/hybrid working, an open holiday policy with no upper limit, and support for volunteering activities.

• Growth & Development: Opportunities for continuous professional development, career progression, and exposure to global teams.

• Inclusive, Supportive Culture: A workplace committed to diversity, equity, and inclusion, fostering a collaborative environment where individual contributions are valued and well-being is prioritized.

• Impact & Purpose: The opportunity to contribute to technology that drives global economic inclusion and positively impacts lives.

Working Hours:

The standard working hours for this role are approximately 40 hours per week. The company offers flexible working arrangements, including remote and hybrid options, allowing employees to manage their schedules effectively while ensuring business needs and project timelines are met.

📝 Enhancement Note: The salary estimate is based on typical market rates for senior-level software developers in the UK, adjusted for the specific tech stack and responsibilities. The benefits listed are comprehensive, covering financial security, work-life balance, professional growth, and a strong emphasis on company culture and purpose, which are attractive to experienced professionals.

🎯 Team & Company Context

🏢 Company Culture

Industry: Technology, specifically focused on mobile device financing and security solutions. Trustonic operates at the intersection of telecommunications, finance, and cybersecurity, providing a unique service that enables economic inclusion globally.

Company Size: Trustonic is an established technology company, likely employing between 201-500 employees based on typical growth trajectories for companies in their niche. This size offers a balance between the resources of a larger organization and the agility and close-knit feel of a smaller one.

Founded: Founded in 2012, Trustonic has a decade of experience in the market, indicating a stable and mature company with a proven business model and established technology.

Team Structure:

• The UI development team is likely integrated within a larger engineering department, potentially comprising 5-10 UI developers, reporting to a Head of Frontend or Engineering Manager.

• This team will work closely with backend engineering teams, product managers, UX/UI designers, and potentially QA engineers.

Methodology:

• Data Analysis & Insights: While primarily a development role, understanding how user behavior data (e.g., from analytics tools) informs UI/UX decisions is valuable.

• Workflow Planning & Optimization: The role involves optimizing frontend workflows, component libraries, and development processes for efficiency and scalability.

• Automation & Efficiency: Implementing automated testing, CI/CD, and efficient development practices are key to delivering high-quality software rapidly.

Company Website: https://www.trustonic.com/

📝 Enhancement Note: Trustonic's mission of making smartphones affordable and enabling digital finance is a strong differentiator. The company culture code emphasizes collaboration, diversity, and doing the right thing, suggesting a supportive and purpose-driven environment. The hybrid and remote-friendly approach aligns with modern work expectations. The company's age indicates stability and market experience.

📈 Career & Growth Analysis

Operations Career Level: This role is classified as "Senior," indicating a position requiring extensive experience (5-10 years) and the ability to lead technical initiatives. A Senior UI Developer is expected to be a subject matter expert in frontend technologies, capable of mentoring junior developers, contributing to architectural decisions, and driving best practices within the team. The scope includes not just coding but also influencing technical direction and ensuring the quality and scalability of the user interface.

Reporting Structure: The Senior UI Developer will likely report to an Engineering Manager or Head of Frontend Engineering. They will collaborate extensively with backend engineers, product managers, and designers. While reporting to a manager, the "senior" title implies a high degree of autonomy and responsibility for their work streams and contributions to the overall platform.

Operations Impact: The UI Developer's impact is directly tied to the user experience of Trustonic's operator web portal, which is central to their business model of device financing and lifecycle management. A well-designed, performant, and intuitive portal directly influences customer adoption, satisfaction, and operational efficiency for their telecom partners. This role is crucial in translating complex platform capabilities into a usable and valuable tool for clients, thereby impacting Trustonic's revenue and market position.

Growth Opportunities:

• Technical Specialization: Deepen expertise in React, TypeScript, GraphQL, and related frontend technologies, potentially becoming a lead architect for frontend systems.

• Leadership Development: Progress into a Lead UI Developer or Team Lead role, taking on more direct management and mentorship responsibilities.

• Cross-functional Expertise: Gain deeper understanding of backend systems, cloud infrastructure (AWS), and product strategy through close collaboration.

• Architectural Influence: Contribute significantly to the technical direction and architectural decisions for the frontend of Trustonic's platform.

• Industry Exposure: Work on innovative technology that drives economic inclusion, providing a unique purpose-driven career path.

📝 Enhancement Note: The "Senior" designation implies more than just coding; it involves technical leadership, mentoring, and strategic input. The growth opportunities are geared towards deepening technical mastery, moving into leadership, or broadening expertise across the tech stack and product lifecycle, all within a company with a meaningful social impact.

🌐 Work Environment

Office Type: The role is described as "remote/hybrid," with attendance required at the Winnersh office "from time to time." This suggests a modern work environment that prioritizes flexibility while maintaining opportunities for in-person collaboration and team building. The Winnersh office likely serves as a hub for key meetings, workshops, and team syncs.

Office Location(s): The primary office location mentioned is Winnersh, United Kingdom. This location is in Berkshire, an area known for its technology and business presence. The hybrid model means employees can work from home for the majority of the time, commuting to Winnersh for specific, planned events.

Workspace Context:

• Collaborative Environment: Opportunities for in-person collaboration will be present during office visits, facilitating brainstorming, problem-solving, and team cohesion.

• Operations Tools & Technology: Employees will have access to the standard company technology stack, including development tools, collaboration platforms (e.g., Slack, Teams, Jira), and secure remote access to company systems. The emphasis on React 18, TypeScript, and AWS suggests a modern and well-equipped development environment.

• Team Interaction: While primarily remote, scheduled office days and virtual communication channels will ensure regular interaction with the UI development team, backend engineers, and product stakeholders.

Work Schedule: The role is full-time, with approximately 40 working hours per week. The hybrid and remote nature of the work allows for flexibility in daily scheduling, enabling individuals to balance work responsibilities with personal commitments, provided project deadlines and meeting requirements are met.

📝 Enhancement Note: The hybrid nature of the role is a key aspect, offering flexibility while ensuring the benefits of in-person interaction for collaboration and team building. The Winnersh office likely provides a professional and well-equipped space for these in-person engagements.

📄 Application & Portfolio Review Process

Interview Process:

• Initial Screening: A brief call with a recruiter to assess basic qualifications, experience, and cultural fit. This stage will likely cover your understanding of the role and your career aspirations.

• Technical Interview (Coding Challenge/Live Coding): Expect a practical assessment focusing on React, TypeScript, and problem-solving skills. This might involve a live coding exercise or a take-home challenge that requires building a small component or feature, demonstrating your ability to handle core tasks.

• Technical Deep Dive: An interview with engineering leads or senior developers to discuss your experience in depth. This will focus on your approach to building complex UIs, working with GraphQL, state management, performance optimization, and testing. Be prepared to discuss your portfolio projects in detail.

• Team/Cultural Fit Interview: A conversation with potential team members (UI developers, backend engineers, product managers) to evaluate collaboration style, communication skills, and alignment with Trustonic's culture code.

• Final Interview: Potentially with a senior engineering leader or hiring manager to discuss overall fit, strategic thinking, and long-term potential.

Portfolio Review Tips:

• Curate Selectively: Showcase 2-3 of your strongest projects that best align with the role's requirements (React 18, TypeScript, GraphQL, Ant Design).

• Highlight Key Contributions: For each project, clearly articulate your specific role, the challenges you faced, the solutions you implemented, and the measurable outcomes or impact.

• Demonstrate Technical Depth: Be ready to walk through the code, explain architectural decisions, discuss state management patterns, and detail your testing strategies.

• Showcase Problem-Solving: Explain how you tackled complex UI challenges, performance bottlenecks, or integration issues.

• Emphasize Collaboration: If applicable, describe how you worked with designers, backend engineers, or other stakeholders.

• Accessibility & Responsiveness: If possible, highlight projects where accessibility (WCAG) and robust responsive design were key considerations.

Challenge Preparation:

• React Fundamentals: Revisit core React concepts (hooks, context, reconciliation, performance optimizations).

• TypeScript Mastery: Prepare for questions on advanced types, generics, utility types, and best practices for TypeScript in large codebases.

• GraphQL Concepts: Understand GraphQL queries, mutations, subscriptions, and how to effectively integrate with APIs like AppSync.

• State Management: Be ready to discuss trade-offs between different state management solutions (React Query, Zustand, Redux) and when to use each.

• Testing Strategies: Review Jest and React Testing Library best practices for component and integration testing.

• Performance Tuning: Familiarize yourself with common frontend performance bottlenecks and optimization techniques.

📝 Enhancement Note: The interview process is structured to thoroughly assess technical skills, problem-solving abilities, and cultural fit. A strong, well-prepared portfolio is essential for demonstrating practical experience, especially for a senior role. Candidates should be ready to articulate not just what they built but why and how, with specific examples.

🛠 Tools & Technology Stack

Primary Tools:

• React 18: The core framework for building the operator portal. Proficiency in its latest features (hooks, context) and performance optimizations is paramount.

• TypeScript: Essential for writing robust, scalable, and maintainable JavaScript code, reducing runtime errors and improving developer productivity.

• Ant Design: The primary component library for building the UI. Experience with its components, theming, and customization is expected.

• Vite: A modern frontend build tool, known for its speed and efficiency. Familiarity with its configuration and features is beneficial.

• Jest & React Testing Library: Standard tools for writing comprehensive unit and integration tests for React applications, ensuring code quality and reliability.

Analytics & Reporting:

CRM & Automation:

• AWS AppSync: The managed GraphQL service used for API integration, providing real-time data synchronization and offline capabilities.

• AWS Cognito: The identity and access management service for user authentication and authorization.

• Git: Standard version control system for collaborative development and code management.

• Jira/Confluence (Likely): Common tools for project management, issue tracking, and documentation in Agile environments.

📝 Enhancement Note: The technology stack is modern and aligned with current industry best practices for frontend development. Expertise in React 18, TypeScript, and GraphQL is non-negotiable. Familiarity with Ant Design and Vite will be highly beneficial. The integration with AWS services (AppSync, Cognito) is a key technical requirement for this role.

👥 Team Culture & Values

Operations Values:

• Doing the Right Thing: A core value that extends to ethical development practices, code quality, and considering the broader impact of technology on users and society.

• Collaboration & Going Together: Emphasis on teamwork, open communication, and supporting colleagues to achieve shared goals. This value is crucial for effective cross-functional work.

• Flexibility & Working at Your Best: Trustonic values enabling employees to work in ways that optimize their productivity and well-being, whether remotely or in the office.

• Diversity & Inclusion: A commitment to celebrating differences and ensuring an equitable environment for all employees, recognizing the strength that diverse perspectives bring.

• Purpose-Driven Innovation: A drive to create technology that has a tangible positive impact, such as enabling economic inclusion through accessible digital finance.

Collaboration Style:

• Cross-functional Integration: The UI team is expected to work seamlessly with backend engineers, product managers, and designers, fostering a holistic approach to product development.

• Process Review & Feedback: An environment that encourages open discussion about development processes, code quality, and UX improvements, with a culture of constructive feedback.

• Knowledge Sharing: Encouraging the sharing of best practices, learnings, and technical insights among team members, potentially through pair programming, code reviews, and internal presentations.

• Agile & Iterative: Working in an agile framework, likely involving iterative development cycles, regular stand-ups, and adapting to evolving requirements.

📝 Enhancement Note: Trustonic's culture code provides a clear framework for how the company operates. The emphasis on "doing the right thing," "going together," and "working at your best" suggests a supportive, ethical, and flexible work environment. This is particularly relevant for a Senior UI Developer who will be expected to uphold these values in their technical contributions and team interactions.

⚡ Challenges & Growth Opportunities

Challenges:

• Balancing Feature Development with Technical Debt: In a fast-moving SaaS environment, there's a constant tension between delivering new features and maintaining code quality, optimizing performance, and addressing technical debt. This role will require strategic decision-making to balance these priorities.

• Scalability of UI Components and Architecture: As Trustonic's platform grows, ensuring the UI components and overall architecture remain scalable, performant, and maintainable will be a continuous challenge.

• Integrating Complex Backend Services: Effectively integrating with sophisticated AWS GraphQL APIs and authentication flows requires deep technical understanding and robust error handling strategies.

• Cross-Functional Alignment: Ensuring consistent understanding and execution across diverse teams (product, backend, design) on UI requirements and technical implementation can be challenging.

• Staying Ahead of Frontend Trends: The frontend landscape evolves rapidly; continuously learning and adopting new best practices and technologies while maintaining stability is an ongoing challenge.

Learning & Development Opportunities:

• Advanced React & TypeScript: Opportunities to deepen expertise in cutting-edge frontend patterns, performance tuning, and advanced TypeScript features.

• Cloud & API Integration: Gaining hands-on experience with a wider range of AWS services and complex backend integrations.

• Design Systems & UX: Developing a stronger understanding of design principles, UX best practices, and contributing to a mature design system.

• Technical Leadership & Mentorship: Opportunities to mentor junior developers, lead feature initiatives, and contribute to architectural discussions.

• Industry Impact: Working on a product that directly contributes to global economic inclusion provides a unique sense of purpose and learning about FinTech and Telecoms intersection.

📝 Enhancement Note: The challenges presented are typical for a senior role in a growing tech company, requiring strategic thinking and proactive problem-solving. The growth opportunities are well-aligned with career progression in frontend development, offering paths for technical specialization, leadership, and broader system understanding.

💡 Interview Preparation

Strategy Questions:

• UI Strategy: "Describe your approach to designing and developing a scalable, reusable component library within a large React application. How would you ensure consistency and maintainability across different teams?" (Prepare to discuss Ant Design, design tokens, and versioning.)

• Technical Leadership: "How do you balance the need for rapid feature delivery with the importance of addressing technical debt and ensuring code quality? Provide an example from your experience." (Focus on prioritization, Agile methodologies, and communication with stakeholders.)

• Problem-Solving: "Imagine a scenario where the operator portal is experiencing slow load times for users in a specific region. What steps would you take to diagnose and resolve this performance issue?" (Prepare to discuss browser developer tools, network analysis, caching strategies, and potential backend interactions.)

Company & Culture Questions:

• Culture Fit: "Trustonic's culture code emphasizes 'doing the right thing' and 'going together.' How do these values translate into your day-to-day work as a developer?" (Connect your personal work ethic and collaboration style to these values.)

• Team Dynamics: "How do you typically collaborate with backend engineers and product managers to ensure successful feature delivery? What challenges have you faced, and how did you overcome them?" (Highlight communication skills, proactive engagement, and conflict resolution.)

• Impact & Purpose: "This role contributes to making smartphones affordable and enabling digital finance globally. How does working on a product with such a social impact motivate you?" (Express genuine interest in Trustonic's mission.)

Portfolio Presentation Strategy:

• Storytelling: For each project, frame it as a narrative: the problem, your solution, the technologies used, and the outcome.

• Focus on Relevance: Prioritize projects that showcase your skills in React 18, TypeScript, GraphQL, and Ant Design.

• Technical Deep Dive: Be prepared to explain architectural choices, state management patterns, testing methodologies, and performance optimizations.

• Quantify Impact: Whenever possible, use metrics to demonstrate the success of your work (e.g., performance improvements, user adoption rates, reduction in bugs).

• Interactive Walkthrough: If presenting live, be ready to navigate the application, highlight key code snippets, and answer detailed technical questions.

📝 Enhancement Note: Interview preparation should focus on demonstrating not only technical proficiency but also strategic thinking, problem-solving capabilities, and alignment with Trustonic's values. The portfolio is a key tool for illustrating practical application of skills, so candidates should be ready to discuss it in detail.

📌 Application Steps

To apply for this Senior UI Developer position:

• Submit Your Application: Click the application link to submit your resume and any supporting documents.

• Tailor Your Resume: Ensure your resume highlights your experience with React 18, TypeScript, GraphQL, AWS services (AppSync, Cognito), Ant Design, and relevant testing frameworks. Use keywords from the job description to optimize for ATS.

• Prepare Your Portfolio: Select 2-3 of your strongest projects that best demonstrate your skills in building complex, modern UIs. Be ready to discuss your contributions, technical decisions, and the impact of your work. Ensure your GitHub or personal portfolio link is clearly visible.

• Practice Interview Responses: Prepare thoughtful answers to common interview questions, including strategy-based questions, behavioral questions, and technical deep dives. Practice articulating your experience and problem-solving approach clearly and concisely.

• Research Trustonic: Understand the company's mission, culture code, and the impact of their technology. This will help you tailor your responses and demonstrate genuine interest.

⚠️ Important Notice: This enhanced job description includes AI-generated insights and operations industry-standard assumptions. All details should be verified directly with the hiring organization before making application decisions.