Shopify Plus Development Agency

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Shopify Plus stores typically need more than the standard theme store can offer: custom checkout logic, multi-currency and multi-region setups, complex integrations with ERP and inventory systems, and performance that holds up during high-traffic sales events like Black Friday without buckling under load.

We develop custom Shopify Plus storefronts and the backend integrations they depend on, working directly with the platform's advanced features — Shopify Functions, Scripts, and the Plus-exclusive checkout customisation options — rather than forcing a standard-Shopify approach onto a catalogue and business model that's outgrown it.

Whether you're migrating an established store onto Plus, launching a new high-volume brand, or need deep integration work with existing enterprise systems, we bring the same WordPress-era discipline around performance, SEO preservation and stakeholder process to Shopify Plus development.

Why choose Flex Digital

Deep Shopify Plus platform expertise

We work directly with Shopify Functions, Scripts and Plus-exclusive checkout customisation, not just theme-level changes.

Enterprise integration experience

ERP, inventory, fulfilment and CRM integrations are a routine part of our Shopify Plus development work.

Built for peak traffic

Performance and scalability planning specifically account for high-traffic sales events, not just average-day load.

Migration expertise without losing SEO

Moving to Shopify Plus from another platform is planned with URL mapping and redirect strategy to protect existing rankings.

Our process

1

Requirements and integration mapping

We map required integrations (ERP, inventory, fulfilment, CRM) and custom checkout logic before development starts.

2

Custom theme development

A bespoke Shopify Plus theme is built around your brand and catalogue, not adapted from a generic template.

3

Checkout customisation

Shopify Functions and Scripts are used to implement checkout logic standard Shopify can't support.

4

Integration build and testing

Backend integrations are built and load-tested ahead of launch, particularly around peak-traffic scenarios.

5

Launch and peak-readiness support

We provide dedicated support around major sales events, when platform stability matters most.

What's included

  • Custom theme development on Shopify Plus
  • Checkout customisation using Shopify Scripts and Functions
  • ERP, inventory and fulfilment system integrations
  • Multi-currency and multi-region storefront setup
  • Performance and scalability planning for peak sales periods
  • Platform migration planning with SEO and URL preservation
  • Custom app development where off-the-shelf apps fall short
  • Ongoing Shopify Plus development and optimisation support

When a store has genuinely outgrown standard Shopify

The clearest signal a business needs Shopify Plus rather than standard Shopify is checkout: if you need custom logic at checkout — complex discount stacking, B2B pricing tiers, subscription and one-time purchase combinations in a single cart — standard Shopify's checkout simply can't be customised to that degree, while Plus opens this up through Shopify Functions.

The second signal is integration complexity: businesses running significant volume typically need real-time inventory sync with a warehouse management system, automated order routing to multiple fulfilment centres, or ERP integration that standard Shopify apps handle poorly at scale. We build and maintain these integrations as core infrastructure, not bolted-on afterthoughts likely to break under load.

Related guides

Frequently asked questions

How is Shopify Plus different from standard Shopify?

Shopify Plus offers checkout customisation (via Shopify Functions and Scripts), higher API rate limits for integrations, multi-store/multi-currency management, and dedicated platform support — features standard Shopify plans don't include.

Can you migrate our existing store to Shopify Plus?

Yes, including full URL mapping and redirect planning to protect existing SEO rankings and customer bookmarks through the migration.

Do you build custom checkout logic?

Yes, using Shopify Functions and Scripts — this is one of the main reasons businesses move to Plus, and a core part of our development work on the platform.

Can the store handle Black Friday-level traffic?

Yes, performance and scalability planning for peak sales events is a standard part of our Shopify Plus builds, not an afterthought addressed only when problems occur.

Do you integrate with our existing ERP or inventory system?

Yes, ERP and inventory integrations are a routine part of Shopify Plus development for established, higher-volume businesses.

Talk to us about Shopify Plus Development Agency

Tell us about your project and we'll get back to you with next steps.

hello@flex-digital.com