Salary: £70,000 - 80,000 per year Requirements: English proficiency and UK work authorisation 5 years commercial full stack experience with strong PHP background Strong architecture-level proficiency in PHP Experience with modern JavaScript and front-end patterns Proficiency in PostgreSQL/MySQL and relational data modelling Experience with API design, integrations, and web services Familiarity with Git workflows and code review leadership Knowledge of testing practices (unit/integration; Behat strongly preferred) Strong Moodle experience (plugins/themes, upgrade paths, performance considerations) - desirable Knowledge of Docker and Linux in production-like environments - desirable Familiarity with CI/CD pipelines and release management - desirable Understanding of authentication protocols (OAuth2/SAML/SSO etc.) - desirable Familiarity with WordPress - useful, not core Responsibilities: Lead the design, build and maintenance of custom Moodle plugins, themes and core feature enhancements Write high-quality, secure, reusable PHP and deliver robust front-end experiences Architect and implement RESTful APIs, integrations, and reliable data flows between systems Own and drive code review quality, engineering standards, and best practices Mentor and support other developers through pairing, coaching, unblocking, and raising capability Take accountability for software quality, including testing strategy, maintainability, performance, and scalability Write and maintain unit tests and Behat tests, ensuring meaningful coverage Diagnose complex issues across application and infrastructure layers and drive resolution Lead performance optimisation and scalability improvements Ensure compliance with accessibility standards, GDPR, and data protection by design Strengthen QA processes and ensure data integrity, including release readiness Work closely with product and design teams to shape solutions Translate stakeholder needs into technical plans Communicate trade-offs clearly and proactively manage technical risk Participate in agile delivery cycles, including estimation, planning, retros, and continuous improvement Stay current with Moodle ecosystem changes and recommend upgrades/approaches Drive improvements to developer experience through tooling, CI/CD, environments, and documentation Help define responsible, effective use of AI coding tools across the team Technologies: AI API Architect CI/CD Docker Git Support JavaScript Linux MySQL PHP PostgreSQL SAML Web WordPress Fullstack More: At Action Sustainability, we are a leading consultancy committed to inspiring sustainable business practices. With a team of over 60 dedicated professionals, we work at the forefront of sustainability and supply chain issues, partnering with renowned organisations such as the NHS and Houses of Parliament. We are based in Old Street, London and offer a hybrid working model, allowing flexibility with 1 day per week in the office. Our benefits package includes a competitive salary range of £70,000 - £80,000, 25 days plus 8 statutory holidays, enhanced maternity/paternity pay, a fitness allowance, and an 8% employer pension contribution. We champion a close-knit culture with a flat hierarchy, ensuring direct communication with our leadership. Join us and be part of a team that is transforming the approach to sustainability through innovative technology and solutions. last updated 7 week of 2026