Shopify Plus Developer & Conversion Lead

Freelance or on staff – open on structure, scoped by workload.
Location: Flexible, Cardiff preferred, open to remote for the right candidate. Remote candidates need at least 4 hours’ overlap with UK working hours. (
Salary: Competitive, benchmarked to location
Role Type: Freelance or full-time
Reports to: Head of Brand Marketing & Ecommerce

The Role

Our client is a high-growth, design-led health and wellness brand pioneering innovation in shaker bottles, blending appliances, and supplement accessories, with a global presence spanning direct-to-consumer, retail, private label, and brand-to-brand.
Using Shopify as their ecommerce platform, they currently run a live US store, with a UK and EU store next. As part of their next phase of growth, they have upgraded to Shopify Plus, specifically to enable multi-entity support and expansion into dedicated regional stores, with ambitious plans to add further expansion stores as their reach grows.

We are looking for one senior person to own our client's website, checkout, and conversion programme end to end. This is a broad technical role. You will need to be genuinely capable across the Shopify ecosystem, know the ins and outs of Shopify Plus, and be comfortable building and shipping stable releases and fixes. You will also own conversion: deciding what to build and test next from the data, and being accountable for the results.

You will work to a defined list of priorities agreed with the marketing team, and use your experience and expertise to suggest and implement optimisations that give our client's customers the smoothest possible shopping experience.

What You’ll Be Doing

Platform and architecture: Build and maintain our client's Shopify theme architecture, including reusable PDP, collection, and bespoke page templates.
Build out the UK and EU store and Shopify Markets architecture from the current setup, and plan for further expansion stores.
Configure and maintain Shopify B2B functionality natively within the platform.
Checkout: Develop and ship Checkout Blocks and extensions (upsell, delivery estimate, thank-you page, checkout branding) to enhance the checkout experience and drive higher conversion.
CRO strategy: Own the CRO roadmap: audit the funnel, form hypotheses, prioritise by impact and effort, and agree the plan with the marketing team.
Set up and run A/B and phased tests, with a baseline and success metric for every change, and report results plainly, including what did not work.
Collect and analyse site usage data on an ongoing basis (GA4, Shopify Analytics, and behaviour tools such as Microsoft Clarity), measure performance, and implement fixes where needed.
Migration and SEO: Handle store migrations, including URL redirect mapping, hreflang, and multi-store SEO, alongside the content team, and monitor search visibility after launches.
Integrations: Integrate Shopify with third-party platforms or external suppliers, e.g., 3PL/fulfilment, payment, loyalty, Klaviyo, Gorgias, ad platform pixels and conversion APIs, and TikTok Shop.
Work with the Ops team on order, inventory, and fulfilment logic where it intersects with the platform.
Liaise directly with external technical suppliers and app vendors to scope, implement, and debug integrations.
Quality and performance: Ensure both mobile and desktop performance, accessibility, and functionality are consistently high.
Work on staging, test properly, release safely, and troubleshoot platform issues when they arise.
Keep clear documentation, and make sure our client owns all theme and extension code.

What We’re Looking For

Demonstrable Shopify Plus development experience. Bonus if you are able to show what you have actually built (a live store, specific theme, or checkout work you can walk us through). Formal qualifications or agency pedigree are not required: we care about what you can ship, not how you learned to build it.
Strong Liquid development skills: comfortable building custom themes, blocks, and templates from scratch, not just editing an existing one.
Hands-on experience with Shopify Plus Checkout Extensibility and Shopify app development.
Experience with Shopify Markets, multi-entity, or multi-store architecture. This is a build-from-scratch project, not maintenance of something live.
An understanding of the SEO implications of store migrations (redirect mapping, duplicate content across regions). You will not be expected to create the content, but will need to understand how it is used.
Real CRO experience: you can show tests or changes you ran, the data behind them, and the results. Comfortable with GA4, GTM, and tracking set-up.
Comfortable working directly with a brand team, rather than through an agency structure: able to scope your own technical recommendations and justify suggestions, not just execute.
Able to own correct, production-safe work with minimal supervision. Multi-store and checkout changes affect live customer orders, so this is about reliability and judgement, not just technical skill.
Comfortable working with Shopify’s GraphQL, Admin API, CLI, webhooks, and third-party integrations.
Confident communicating directly with external technical partners and vendors.
Nice to have: Shopify B2B, 3PL, or ERP integration experience, Shopify Flow, an A/B testing tool, and experience with a consumer or health and wellness brand.

What This Role Is Not

This isn’t a design or creative-direction role. You will be implementing against designs and briefs from the creative team.
It is not a narrow developer role. We need someone with a genuinely diverse skillset, but also someone who can own when a specific task is beyond them and needs expert knowledge.

How We’ll Measure Success

Conversion rate, checkout completion, average order value, page speed, release stability, and the quality and results of the CRO roadmap.

Your First 90 Days

Days 1 to 30: Audit the US store, take ownership of the codebase, and agree on the priority list and the UK and EU build plan.
Days 31 to 60: Deliver the UK and EU store build and the first checkout blocks.
Days 61 to 90: Run the first tests, report the results, and agree on the next quarter’s roadmap.

How We’ll Hire

A portfolio walkthrough, a short practical task (a conversion audit of our client's US store with a scoped recommendation), and an interview with the marketing and creative team.

Shopify Plus Developer -65740160377