Senior Engineer

Our client is a well-established charity that mobilises volunteers to support individuals, local communities and public health services across the UK.

They have developed a volunteering platform. Your role is to be the skilled and motivated Senior Engineer who helps guide the design, development, and delivery of the platform's Next.js front-end.

Reporting to the CTO, you'll manage a small team of offshore engineers in your time zone while actively contributing to code, architectural decisions, and quality outcomes yourself.

Our client's engineering today is a mix of hands-on development and AI-assisted coding, without disciplined TDD.

You'll work directly with the CTO and the other Senior Engineer to move the team to an AI-assisted + TDD way of working — specs and tests agreed up front, AI coding agents handling the bulk of initial implementation, and engineering time increasingly spent on quality: refactoring, verification and system assurance rather than hands-on typing.

You'll be critical for setting this standard, both by example in your own code and at each code review, especially in how rigorously AI-generated output is verified before it ships.

We're looking for someone who has already worked this way and can bring that discipline in from day one — the benchmark we're aiming for is how leading AI labs build software.

You'll thrive here if you enjoy the shift from author to architect and editor — defining intent, catching what AI misses, and raising the bar for the team around you.

What you will be doing

Hands-On Development

• Design, build and maintain features primarily in Next.js, React and TypeScript
• Write clean, testable code that adheres to team standards
• Partner with team members to debug issues and deliver robust solutions

Driving the AI-Assisted + TDD Transition

• Work with the CTO and the other Senior Engineer to establish spec-first, test-first practices across the team
• Help define what "spec and tests agreed before coding starts" looks like in practice
• Coach engineers through the shift from ad hoc AI-assisted coding to disciplined TDD

Spec & Test-First Discipline

• Contribute to and validate the specification (stories, acceptance criteria, architecture, UI, data structures) before coding starts, so decisions are made once and not relitigated mid-sprint
• Write or review unit tests against the spec ahead of implementation
• Use AI coding agents (e.g. Claude Code, GitHub Copilot) to accelerate implementation once spec and tests are agreed

Quality, Refactoring & Assurance

• Treat QA, refactoring and system health as the majority of engineering time, not an afterthought
• Verify AI-generated code for correctness, security and maintainability rather than assuming it's right
• Use tooling such as SonarQube to maintain code quality
• Raise blockers early

Technical Guidance & Mentorship

• Line-manage and provide technical leadership to a small team of offshore engineers in your timezone
• Keep the team aligned with project goals and technical standards
• Give complete, thought-through feedback during code review and handover
• Model the spec-first, test-first approach by example

Collaboration & Communication

• Work closely with Product, Design and QA across the feature and story delivery flow
• Proactively engage — raise questions or problems rather than waiting to be asked
• Be available for quick syncs during the day
• Clearly communicate progress, risks and technical decisions to the CTO and relevant stakeholders
• What you need to know

Knowledge

• Strong experience in front-end development with Next.js, React and TypeScript
• Component architecture, server-side rendering/static generation, and modern Next.js patterns (e.g. App Router, server components)
• RESTful API integration from the front-end
• Deep, practical understanding of test-driven development (TDD) — writing unit tests against a spec before implementation, not after
• AI-assisted, agentic coding workflows and tools (e.g. Claude Code, GitHub Copilot), including how leading AI labs apply these practices to their own engineering, and how to critically verify AI-generated output
• CI/CD pipelines and code quality tooling (e.g. SonarQube)
• Strong problem-solving skills and comfort working in a spec-first, collaborative environment

Skills

• Next.js, React, TypeScript, JavaScript
• RESTful APIs, API integration
• Test-driven development and unit testing frameworks (e.g. Jest, React Testing Library) — end-to-end/Cypress testing sits with the Automated QA function, so this role collaborates with them on coverage rather than owning it directly
• AI coding agents/assistants (e.g. Claude Code, GitHub Copilot) used in a disciplined, spec-first workflow
• Coaching and embedding new engineering practices within a team
• Git, GitHub, CI/CD (e.g. Azure DevOps)
• Code quality and static analysis tooling (e.g. SonarQube)
• Design-system implementation and Figma-to-code workflows
• Clear written and verbal communication

Experience

• 5-7 years engineering experience, with strong recent focus on front-end/Next.js or React development
• Proven experience working in an AI-assisted + TDD development workflow — not just AI-assisted coding, but
• disciplined test-first practice — ideally close to how Anthropic and similar organisations build software
• Experience leading or actively driving a team’s transition to a new engineering methodology, not just working
• within an established one
• 1-2 years experience managing or mentoring developers, ideally in an offshore/distributed team setup
• Bachelor’s degree in Computer Science, Software Engineering or a related field (or equivalent experience)
• Experience collaborating closely with Product, Design and QA in a fast-moving, sprint-based environment
• Comfort setting technical direction directly with the CTO, without a Tech Lead layer in between
• Track record of shipping production features end-to-end, from spec through to release