Senior Full Stack Developer

The Role:
Brook Green Supply (BGS) is a leading independent B2B energy supplier, delivering tailored energy supply and Net-Zero solutions to industrial and commercial consumers.

The Senior Full Stack Engineer will design, build and support reliable, accessible and high-performing web applications that enable our teams and customers to work effectively. You will lead technical delivery across modern frontends, APIs and backend services, balancing product needs with maintainability, security and performance.

Working closely with Product, Design and Engineering colleagues, you will make sound architectural decisions, communicate trade-offs and support the development of other engineers. You will take responsibility for features from early design through release and ongoing improvement.

Essential Functions of the Job:

• Lead the design, development and delivery of web applications using Next.js and TypeScript, with a focus on usability, accessibility and responsive design.
• Build and maintain backend services and APIs, including REST or GraphQL integrations, using Python and FastAPI where appropriate.
• Own technical features end to end, from requirements and implementation through automated testing, deployment, monitoring and support.
• Apply frontend engineering fundamentals, including performance optimisation, state management, component design and accessibility.
• Improve continuous integration and deployment (CI/CD) processes, automated test coverage and production observability.
• Make and document proportionate technical decisions, explaining trade-offs relating to delivery speed, quality, scalability and maintainability.
• Work closely with Product and Design to shape practical technical solutions that meet user and business needs.
• Review code constructively, mentor engineers and lead technical work across features or projects.
• Investigate production issues, resolve root causes and improve the reliability of applications and services.
• Contribute to reusable engineering patterns, documentation and shared components to improve team delivery.

Skills & Experience Required:

• Strong commercial experience building modern web frontends with Next.js and TypeScript.
• Solid understanding of accessibility, web performance, responsive design and frontend state management.
• Experience building and consuming REST or GraphQL APIs, with confidence working across frontend and backend systems.
• Backend development experience, ideally with Python and FastAPI.
• Hands-on experience of CI/CD, automated testing from unit to end-to-end level, and observability in production environments.
• Sound technical judgement, including a track record of evaluating trade-offs and explaining decisions clearly.
• Experience mentoring engineers, reviewing code or leading the technical delivery of projects.
• Clear communication skills and a collaborative approach to working with Product and Design teams.
• Experience with design systems or component libraries, such as Storybook, is desirable.
• Experience with frontend testing tools, such as Playwright, Cypress or Testing Library, is desirable.
• Familiarity with Azure, containers or Kubernetes is advantageous.
• Experience with large language models (LLMs), AI-driven user experiences or energy trading systems is advantageous.

Brook Green Supply is committed to ensuring equal opportunities, fairness of treatment, dignity and respect, and the elimination of all forms of discrimination in the workplace for all employees/contractors and job applicants. We will never ask if you have a disability at any point in the recruitment process. However, if you require any specific accommodations during the interview process, please let us know and we will do our best to support you.