Customisation Options
Plus merchants have access to two checkout customisation systems: the legacy checkout.liquid (being deprecated), and the modern Checkout Extensibility platform. Shopify has announced that checkout.liquid will be sunset, so all new customisation work should use Checkout Extensibility.
Checkout Extensibility uses React-based UI extensions that render within defined extension points in the checkout, and checkout branding settings that apply visual customisation via the editor.
Checkout Liquid
Checkout.liquid is a Liquid template file unique to Plus that allows full HTML and CSS modifications to the checkout. If you are currently using it, your customisations will continue to work until Shopify's sunset deadline, but no new development should be done in checkout.liquid.
Migrate existing checkout.liquid customisations to Checkout Extensibility. Most visual customisations (colours, fonts, logos) can be replicated via the Checkout Editor without code.
Checkout Extensibility
Checkout Extensibility is the current Plus checkout customisation platform. It consists of: checkout UI extensions (React components that add content to the checkout), post-purchase extensions (UI on the order confirmation page), and checkout branding settings (visual customisation via Shopify admin).
Extensions are deployed as Shopify app extensions. You can build them as a custom app for your store, or use third-party apps like ReConvert.
Branding Checkout
In Shopify admin, go to Settings, then Checkout, then Customise. The visual editor allows you to change: logo, colours, typography, and corner radius of UI elements.
A fully branded checkout that matches your store design increases trust and reduces abandonment by removing the jarring transition from your custom-designed store to a generic-looking checkout.
Custom Fields
Use Checkout UI extensions to add custom fields: gift message field, business registration number, delivery instructions, or a 'how did you hear about us?' survey. Custom field values are saved as order attributes and visible in the order detail.
Keep custom fields minimal. Every additional field adds friction.
Post-Purchase Pages
The post-purchase page (order confirmation) is a prime location for upsells and data collection. Shopify Plus merchants can add UI extensions to the thank you page: a one-click upsell offer, a survey, a loyalty programme enrolment prompt, or a referral programme share widget.
Post-purchase upsells on the thank you page have high acceptance rates because there is no additional payment friction.
Testing and QA
Test all checkout customisations with real test orders using Shopify's Bogus Gateway payment method. Test edge cases: orders with discount codes, orders with multiple shipping zones, orders from B2B customers with different tax settings.
