Next JS Senior engineer

Position: Next JS Senior engineer
Location: Coventry/London, UK (Hybrid- 1 or 2 days a week from office)
12 months contract position

The Role

This role is designed to strengthen our engineering capability in support of strategic digital transformation initiatives and business-critical web application projects. As a Senior Next.js Engineer, you will design and build modern, high-performance web applications using Next.js App Router, React Server Components (RSC), and Server Actions, delivering scalable solutions that support complex business workflows.

You will be responsible for developing robust full-stack capabilities, including backend APIs, server-side logic, and MongoDB integrations, while applying clean code and SOLID design principles. The role will also focus on performance optimisation through SSR, SSG, ISR, advanced caching, and asset optimisation to maintain excellent Core Web Vitals. In addition, you will implement end-to-end observability using New Relic, ensuring comprehensive logging, tracing, and metrics collection across both client-side and server-side runtimes.

Your responsibilities:

• Design and build robust web applications using Next.js App Router, React Server Components (RSC), and Server Actions.
• Develop and maintain scalable backend APIs to support complex business workflows.
• Design and implement MongoDB data models and database schemas to support application requirements.
• Build efficient server-side logic and integrations across the full application stack.
• Apply clean code practices and SOLID design principles to deliver maintainable and extensible solutions.
• Implement and optimise data-fetching strategies including SSR, SSG, and ISR.
• Develop and maintain advanced caching mechanisms to improve application scalability and performance.
• Optimise application assets and user experiences to achieve strong Core Web Vitals.
• Implement end-to-end observability with New Relic, including logging, tracing, and metrics collection.
• Monitor and troubleshoot application performance across both client-side and server-side (Node.js/Serverless) runtimes, driving continuous improvements in reliability and operational visibility.

Your Profile

Essential skills/knowledge/experience:

• Next.js Expertise: Strong hands-on experience with Next.js App Router, React Server Components (RSC), and Server Actions for building modern web applications.
• React & TypeScript Development: Proficiency in React, TypeScript, JavaScript (ES6+), component-based architecture, and modern frontend development practices.
• Full-Stack Engineering: Experience developing scalable backend APIs, server-side logic, and end-to-end application functionality.
• MongoDB & NoSQL Databases: Strong knowledge of MongoDB, data modelling, schema design, and database integration patterns.
• Software Design Principles: Solid understanding of clean code practices, SOLID principles, and maintainable application architecture.
• Performance Optimisation: Experience implementing SSR, SSG, ISR, caching strategies, and asset optimisation to achieve strong Core Web Vitals.
• Observability & Monitoring: Hands-on experience with New Relic for application monitoring, distributed tracing, logging, and metrics collection.
• Node.js Development: Experience developing and supporting server-side applications using Node.js runtimes.
• Application Troubleshooting: Strong analytical and problem-solving skills with the ability to identify and resolve performance and application issues.
• Agile Delivery: Experience working in Agile/Scrum environments, participating in sprint planning, reviews, retrospectives, and iterative software delivery.

Desirable skills/knowledge/experience:

• Retail Domain Experience: Knowledge of retail business processes and customer-facing digital platforms, preferably within large UK retail organisations.
• Performance & Load Testing: Practical experience with performance, load, and scalability testing using tools such as k6, JMeter, or equivalent.
• Microservices Architecture: Understanding of microservice architecture patterns, distributed systems, and service integration principles.
• MongoDB Administration: Experience with MongoDB configuration, schema design, indexing strategies, and performance optimisation.