GLOSSARY · C
Checkout Extensibility
Shopify’s app-based framework for customising checkout — UI extensions, Functions and branding settings — which replaced checkout.liquid and Shopify Scripts on Plus.
WHY IT MATTERS
Why it matters for a Shopify store.
For years, Plus merchants customised checkout by editing checkout.liquid: fragile, slow to load and impossible to upgrade. Checkout Extensibility moves every customisation into apps and configuration, so Shopify can ship checkout improvements without breaking yours.
It also unlocks things the old way could not do well: Shop Pay compatibility, one-page checkout, custom fields and upsells that work on every device, and discount and shipping logic that runs server-side through Shopify Functions.
HOW CREATIVE LABS HANDLES IT
What we do about it on every project.
01
Audit what checkout.liquid actually did
Most legacy customisations are trust badges, a gift note and a delivery-date field. We list every one before rebuilding anything.
02
Rebuild as UI extensions
Fields, banners, upsells and messaging become checkout UI extensions that survive every Shopify update.
03
Move Scripts to Functions
Discount, shipping and payment logic is rewritten as Shopify Functions, with tests.
04
Brand it in settings
Colours, type and layout through the checkout branding API — no code to maintain.
05
Test on every surface
Desktop, mobile, Shop Pay and accelerated checkouts, with real orders on a development store.
06
Measure checkout conversion
Before and after, per device, so the upgrade is judged on orders rather than opinion.
EXAMPLE
A real example.
A Plus merchant with a 2019 checkout.liquid holding a gift-message field, a trust bar and a free-shipping script.
We rebuilt the field and bar as UI extensions, the shipping rule as a Function and the colours in branding settings. Checkout loaded faster, Shop Pay worked for the first time, and completion rate on mobile rose — tracked over the following month.
COMMON MISTAKES
What usually goes wrong.
Waiting until the deadline
Shopify’s deadlines for checkout.liquid have passed. Stores still on it lose features and cannot use one-page checkout.
Rebuilding everything
Half of legacy customisations are no longer needed. Audit first; many can simply be dropped.
Treating Functions as optional
Scripts stop working. Discount and shipping logic has to move, and it has to be tested.
CHECKOUT EXTENSIBILITY
4 questions
Do I need Shopify Plus?
UI extensions and branding work on all plans; Functions for discounts and shipping and most checkout customisation require Plus.
Can you keep our current checkout look?
Yes. Branding settings and UI extensions can match your fonts, colours and the elements customers rely on, like trust badges or a gift note. We list what your current checkout does before we rebuild any of it.
How long does an upgrade take?
It depends on how much the old checkout did. Most upgrades are a few weeks: audit, rebuild as extensions and Functions, test, then switch. We give a fixed timeline after the audit.
What happens to Shopify Scripts?
Shopify Scripts are being retired in favour of Shopify Functions. We rebuild discount, shipping and payment logic as Functions, which run server-side and work with Shop Pay.
Related terms
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Send us your store. Within one business day you get a short Loom from a senior: the three things we'd fix first, what it would cost, and whether we're the right team for it.
- No pitch deck, no discovery-call theatre
- You keep the audit whether or not you hire us
- Fixed-scope quotes, no hourly surprises
Prefer to talk? Book 20 minutes with Haniel or call +1 855-764-4977