Location: 1 day remote + 1 day on-site in London
Contract: Freelance, approx. 3-month rolling project
Reports to: Technical Lead
Rate: £250 - £350 per day
Start: ASAP
Intro
We’re looking for an experienced Senior Developer to join us on a short-term freelance basis, working directly on-site with our London-based clients two days a week. We’re looking for a self-motivated Senior Developer who’s confident in client-facing environments, able to advocate for the best use of their time, and skilled in shaping tasks as well as delivering work autonomously.
You’ll help bring high-impact ecommerce projects to life, turning design concepts into fast, accessible and beautiful experiences that perform flawlessly.
About UWP
We’re Underwaterpistol, a creative and technical ecommerce agency built for brands that want to stand out. We design, build and grow Shopify Plus stores that deliver measurable results, blending creative thinking with technical precision.
Our developers care deeply about quality, detail, and craft and we’re looking for someone who shares that mindset.
This role involves working closely with our clients on-site, acting as a trusted technical partner. You’ll be responsible for shaping your workload, managing priorities directly with client teams as their primary solo developer and representing UWP with confidence and clarity.
Role Overview
As a Senior Developer, you’ll lead the build and implementation of front-end features, ensuring clean, reusable code and seamless collaboration with designers and strategists. You’ll be hands-on in translating UI/UX concepts into working digital experiences, maintaining our high standards for accessibility, performance, and maintainability.
You’ll need to be comfortable working independently, shaping tasks proactively, and advocating for the most effective use of development time in a client-facing setting.
Key Responsibilities
* Build out design comps accurately and efficiently.
* Write structured, well-organised, reusable code.
* Inspect, debug, and troubleshoot bugs and QA issues.
* Ensure the technical feasibility of UI/UX designs.
* Collaborate closely with other team members and stakeholders.
* Lead on assigned development projects, making technical recommendations, flagging risks, and supporting other developers when needed.
* Help uphold and refine UWP’s development standards and best practices.
* Contribute to internal policies, documentation, and component frameworks.
* Communicate progress clearly with project and delivery teams, ensuring visibility on timelines and blockers.
Skills and Experience
Essential
* Experience with Shopify
* Strong proficiency with HTML5, CSS3, and Vanilla JavaScript.
* Experience working with Liquid (Shopify).
* Understanding of LESS and SASS pre-processing.
* Strong grasp of cross-browser compatibility and responsive development.
* Proficiency with Git (or similar version control).
* Understanding of SEO and UX best practices.
* Excellent attention to detail and a good eye for design.
* Strong communication and documentation skills.
* Portfolio of live projects demonstrating your work.
Nice to Have
* Experience with Gadget
* Familiarity with JavaScript frameworks (React, Vue, Angular).
* Experience with Node.js, Python, Ruby, or PHP.