OnBuy
Senior Full Stack Engineer Contractor
Remote Full Stack Engineering role with clear candidate location fit.
PostedJun 21, 2026
Eligible countries1 accepted country
Seniority signalSenior
Work settingRemote
Accepted candidate locations
United Kingdom
Role overview
Senior Full Stack Engineer Contractor
Requirements and responsibilities
Readable role content extracted into sections for faster review.
Who are OnCommerce?
- OnBuy - The only marketplace in the world to give customers instant Cashback on everything
- easyShop - An all-new marketplace created in collaboration with the easy® family of brands
- Comet - The iconic UK tech brand making its return later this year
End-to-End Engineering Ownership
- Design, build, and maintain full-stack solutions across UI, APIs, and backend systems
- Translate product requirements, designs, and wireframes into scalable, production-ready systems
- Own features from concept → development → testing → release → monitoring
Front-End Excellence
- Build responsive, high-performance user interfaces using modern JavaScript frameworks
- Translate UI/UX designs into clean, maintainable code
- ·Optimise applications for speed, scalability, and usability
Back-End & Platform Engineering
- Design and develop scalable services and APIs
- Work across monolith and microservices architecture (Laravel / PHP services)
- Maintain and evolve legacy systems while building modern, scalable architecture
Quality & Engineering Standards
- Own quality to production — testing is embedded, not a phase
- Write and maintain automated tests (unit, integration, end-to-end)
- Participate in and lead code reviews to ensure high engineering standards
- Debug, troubleshoot, and resolve issues across the stack
Performance & Scalability
- Optimise systems for performance, reliability, and scale
- Work with large-scale data systems (MySQL, NoSQL, search platforms)
- Identify bottlenecks and proactively improve system efficiency
Collaboration & Leadership
- Work in cross-functional teams with Product, Design, QA, and other Engineers
- Mentor and support less experienced engineers
- Communicate technical concepts clearly to non-technical stakeholders
RequirementsEssential
- Strong full stack engineering experience, owning end-to-end delivery
- Proven backend expertise in PHP (Laravel)
- Strong JavaScript (ES6+) skills with modern frameworks (React/Vue/Angular)
- Experience designing and building RESTful APIs and scalable systems
- Experience with MySQL and NoSQL databases (e.g. Couchbase, MongoDB)
- Strong understanding of system architecture and microservices
- Experience with event-driven systems (e.g. RabbitMQ, Pub/Sub) and cloud environments (GCP)
- Familiarity with Docker and CI/CD pipelines
- Strong engineering practices: testing, code quality, and production ownership
Desirable
- Experience in eCommerce or marketplace platforms
- Cloud experience (GCP)
- Experience with NoSQL (e.g. Couchbase) and Search platforms (e.g. Constructor & Solr)
- Experience working in microservices architecture
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