Why this opportunity stands out
Join a business-critical legacy platform upgrade in Leeds/Yorkshire as a senior PHP Full Stack Contractor, outside IR35.
About the role
167 Solutions is recruiting an experienced PHP Full Stack Contractor for a business-critical legacy upgrade project.
You will help modernise an established application while protecting business continuity, improving maintainability and creating a clear route from legacy code to a reliable modern architecture. The assignment needs someone comfortable understanding an existing codebase, making pragmatic technical decisions and delivering improvements incrementally rather than attempting an unsafe wholesale rewrite.
The contract pays £400–£500 per day and is outside IR35. It is suitable for a senior engineer who can contribute across backend PHP, web interfaces, data and integrations. React experience is a bonus, while exposure to Java and/or C# will be valuable in a mixed-technology estate.
Key responsibilities
• Upgrade legacy PHP code and frameworks to supported, secure versions.
• Refactor high-risk components while maintaining existing business functionality.
• Design and build RESTful APIs and reliable integrations with surrounding systems.
• Deliver full-stack features across PHP, JavaScript, HTML and CSS.
• Improve automated testing, code quality, observability, security and performance.
• Plan data and database changes with safe migration and rollback approaches.
• Work with product, technical and operational stakeholders to sequence delivery.
• Document architecture, decisions, dependencies and operational handover.
• Support code reviews, CI/CD improvements and controlled production releases.
What they're looking for
• Expertise in a mainstream PHP framework such as Laravel or Symfony.
• Proven experience upgrading, refactoring or modernising legacy applications.
• Strong SQL and relational database skills, ideally MySQL or PostgreSQL.
• Experience building and consuming REST APIs and third-party integrations.
• Solid JavaScript, HTML5 and CSS3 skills; React experience is a bonus.
• Automated testing experience with PHPUnit and appropriate frontend testing tools.
• Git, dependency management with Composer and modern code-review practices.
• CI/CD, Docker or containerised development, Linux and cloud deployment awareness.
• Knowledge of secure development, performance optimisation and production troubleshooting.
• Java and/or C# experience is desirable for integration with the wider legacy estate.
• Able to operate independently, communicate clearly and deliver within an outside-IR35 engagement.
Benefits
• Outside IR35 contract.
• Leeds / Yorkshire location.
• High-impact legacy modernisation programme.
• Opportunity to influence architecture, engineering standards and the upgrade roadmap.