Overview
The Senior PHP Developer will play a key role in the maintenance, enhancement, and strategic development of a proprietary extensible multi-tenancy data-driven platform that underpins a diverse portfolio of digital solutions across global markets. Architected as a headless, RESTful PHP application, this platform supports scalable content management, dynamic user authentication, and integration with a broad range of frontend technologies and external systems. Working closely with the Principal Developer, Head of Technology, and cross-functional delivery teams, the successful candidate will be responsible for implementing secure, efficient, and maintainable code, whilst contributing to the broader evolution of the platform architecture. This includes driving the decomposition of monolithic functions into modular microservices within a fully cloud-native, event-driven ecosystem. The role demands a strong foundation in PHP development, a product-minded approach to change management, and an understanding of scalable backend systems. The Senior PHP Developer will also contribute to a shared component model and reusability strategy that prioritises maintainability, interoperability, and platform extensibility across client solutions. How you'll make an impact Maintain and extend a proprietary PHP-based platform with a focus on stability, security, and performance. Develop secure, reusable, and scalable containerised backend services using PHP 8, Symfony, and Doctrine ORM. Contribute to the strategic decoupling of platform capabilities into independently deployable Symfony-based microservices, aligned with a cloud-native, event-driven architecture. Ensure compatibility and integration with frontend applications via RESTful APIs (commonly Angular-based, but frontend-agnostic). Apply a productised approach to change management, evaluating bespoke client requests for broader reuse across the platform. Uphold and contribute to platform-wide engineering standards, including secure coding, error handling, and performance optimisation. Collaborate on API design and domain modelling for new services and platform extensions. Support CI/CD workflows and contribute to containerised deployment processes using Docker and Kubernetes. Assist in the identification, resolution, and prevention of bugs and vulnerabilities in production and development environments. Produce and maintain technical documentation, ensuring alignment with team standards and platform governance. Participate in sprint planning, backlog grooming, and peer code reviews. Work closely with security and infrastructure teams to ensure compliance with regulatory and organisational standards. Provide informal mentoring and guidance to mid-level and junior developers within the team. Stay abreast of Symfony ecosystem updates and relevant advancements in PHP, cloud-native design, and scalable backend patterns. About You Background working on a productised platform or multi-tenant system serving multiple clients. Experience integrating with third-party systems including HRIS, payroll platforms, and identity providers (, OKTA). Familiarity with ElasticSearch, secure SFTP data handling, and platform performance monitoring. Understanding of event queue systems and asynchronous processing. Knowledge of frontend-backend integration with Angular or mobile clients via REST APIs. Awareness of privacy-by-design and compliance practices in platform development ( GDPR). Previous experience supporting the migration of monolithic applications to modular service-oriented architectures. Additional Context This is a hands-on engineering role in a technically complex and evolving platform environment. The Senior PHP Developer will work alongside technical leads and cross-functional teams to shape the future of a mission-critical backend system. As part of a strategic shift towards modularity and reusability, this role will contribute directly to the implementation of Symfony-powered microservices, aligning with cloud-native principles and long-term product vision. Eligibility Requirements Must have the Right to Work in the United Kingdom. Compensation and benefits On top of a competitive salary, great teams and exciting career opportunities, we also offer a wide range of benefits. Below are the minimum core benefits you’ll get, depending on your job level these benefits may improve: Minimum of 25 days holiday, plus bank holidays, and the option to ‘buy’ extra days Defined contribution pension scheme, which Gallagher will also contribute to Life insurance, which will pay 4x your basic annual salary, which you can top-up to 10x Income protection, we’ll cover up to 50% of your annual income, with options to top up Health cash plan or Private medical insurance Other benefits include: Three fully paid volunteering days per year Employee Stock Purchase plan, offering company shares at a discount Share incentive plan, HMRC approved, tax effective, stock purchase plan Critical illness cover Discounted gym membership, with over 3,000 gyms nationally Season ticket loan Access to a discounted voucher portal to save money on your weekly shop or next big purchase Emergency back-up family care And many more…