Senior Full-Stack Developer

Salary: £36,000 - 46,000 per year

Requirements

• Strong commercial experience delivering and maintaining production web applications.
• Exceptional attention to detail across technical documentation, application behaviour and interface quality, including edge cases and consistency with the agreed specification.
• Experience leading technical discovery with clients and translating meetings, business processes and ideas into comprehensive system specifications and technical documentation.
• Ability to scope a complete application, identify gaps and dependencies, define acceptance criteria and produce realistic development estimates.
• Strong React experience, with Next.js and TypeScript experience or the technical depth to become productive in them quickly.
• Confidence across the full stack, including APIs, databases, data modelling, authentication and deployment.
• Practical experience building software with Claude Code or equivalent AI coding tools, and willingness to use Claude Code in this role.
• Sound engineering judgement, including the ability to understand, review, debug and improve AI-generated code.
• A practical approach to testing, validation and reliable releases.
• Clear written and verbal communication, including explaining technical decisions to clients and non-technical colleagues.
• Ability to work independently, take responsibility and ask for input when needed.
• Useful additional experience includes working in a digital agency or consultancy across multiple client projects; Astro; code review, mentoring or improving development practices; third-party integrations; interface quality and usability; and WordPress or WooCommerce.
• Ability to attend our Chandlers Ford office two days each week and reliably commute or plan to relocate before starting.
• Bachelors degree required.
• English required.

Responsibilities

• Lead the technical side of client discovery meetings, asking questions to understand business processes, user needs and system goals.
• Turn client conversations into clear, comprehensive technical documentation covering the full system.
• Define functionality, user roles and permissions, user journeys, workflows, data structures, integrations, and security, performance and accessibility requirements.
• Identify gaps, assumptions, dependencies and edge cases, and work with clients and colleagues to resolve them before development.
• Produce scopes of work and technical specifications with clear acceptance criteria, defining what is included or excluded and distinguishing launch requirements from future phases.
• Explain technical options and trade-offs, break scopes into practical development phases and produce realistic estimates.
• Keep documentation up to date as decisions are made and requirements evolve; take ownership of technical specifications and system design and guide clients through them.
• Own technical delivery from the agreed specification through architecture, development, testing, deployment and ongoing improvements.
• Build applications with Next.js, React and TypeScript across interfaces, APIs, databases and integrations.
• Set up and maintain repositories, development environments and deployment pipelines.
• Use Claude Code and other AI development tools effectively, reviewing and validating their output and checking AI-assisted documentation for accuracy.
• Build security, accessibility, performance and maintainability into applications, and test them against agreed requirements and acceptance criteria.
• Review other developers work, help resolve technical problems and contribute to shared development standards.
• Communicate progress, risks and scope changes clearly with colleagues and clients.
• Develop estimates with input from the team and agree delivery plans with the Managing Director.
• Occasionally help with complex issues or integrations on existing WordPress and WooCommerce client websites.

Technologies:

• AI
• Claude Code
• Marketing
• React
• Security
• TypeScript
• Web
• WordPress
• GitHub
• JavaScript
• Fullstack

More:

Were Onlined, a digital agency based in Chandlers Ford, Hampshire, with around 20 years of experience in web design, development, SEO and digital marketing. Were a small team with long-standing client relationships and a growing portfolio of bespoke application development. Youll work directly with our Managing Director and alongside colleagues in design, development, business analysis and project management, with influence over technical decisions and how we deliver projects. This is a full-time, permanent senior role with hybrid working: two days a week in our Chandlers Ford office, with flexibility around how those days are arranged, and flexible working around core hours. Salary is £36,000–£46,000 per year, dependent on experience and discussed openly and early. We offer 31 days holiday including bank holidays, your birthday off, a pension scheme, private medical insurance, free and on-site parking, casual dress, work-from-home flexibility, and budget and time for learning, tools and experimentation. AI is central to how we plan, document and build, and the role offers room to experiment with workflows and help shape our approach.

last updated 41 week of 2026