Shopify Checkout Customisation: What You Can (and Cannot) Change

Why Checkout Customisation Matters

Your checkout is where browsers become buyers. Every friction point, every confusing element, every missed upsell opportunity at checkout is a direct revenue impact. Even small improvements — removing unnecessary form fields, adding trust badges, showing relevant upsells — can increase checkout conversion rates by 10–25%.

But Shopify’s checkout has always been the least customisable part of the platform. Here’s a clear breakdown of what’s possible at each tier.

What Standard Shopify Allows

• Branding — logo, background colour, font, and button colours via Online Store → Themes → Checkout
• Custom form fields — additional notes field, gift message field via order notes
• Shipping rate names — rename “Standard Shipping” to “Free delivery (3-5 days)”
• Discount codes — standard discount code field in checkout
• Payment method display — select which payment methods appear and in what order
• Post-purchase pages — the thank-you page and order status page can be customised via additional scripts (Shopify Admin → Settings → Checkout → Order status page)

What Shopify Plus Allows (checkout.liquid)

Shopify Plus merchants get access to checkout.liquid — the Liquid template file that controls checkout HTML. This enables:

• Full HTML/CSS customisation of the checkout layout
• Custom content sections (trust badges, product guarantees, countdown timers)
• Custom JavaScript for analytics, tracking, and third-party integrations
• Remove or reorder checkout form fields
• Add custom form fields (business VAT number, delivery instructions)

Shopify Functions: Checkout Logic Customisation

Shopify Functions (available on Plus, expanding to standard plans) allow custom server-side logic at checkout. Use cases:

• Custom discount logic (e.g., buy 3 get 1 free, customer-specific pricing)
• Custom shipping rate logic (e.g., show rates based on customer account type)
• Payment customisation (e.g., hide payment methods for certain cart conditions)
• Delivery customisation (e.g., block certain shipping methods for certain products)

Checkout Extensions: Post-Purchase Upsells

Shopify Checkout Extensions allow custom UI components in the checkout (on Plus) and on the post-purchase thank-you page (on all plans). Post-purchase upsell apps like Carthook and ReConvert use these extensions to show a one-click upsell offer immediately after checkout — when buyer excitement is at its peak. Industry average: 5–15% of customers accept a post-purchase upsell.

Checkout Optimisation Without Customisation

Even without deep customisation access, standard Shopify stores can improve checkout conversion by:

• Enabling Shop Pay (Shopify’s accelerated checkout — reduces checkout time by 4x for returning customers)
• Enabling Buy Now Pay Later options (Klarna, Clearpay, Afterpay) — shown to increase AOV by 20–30%
• Adding trust badges in the branding section
• Removing unnecessary checkout steps (Shopify’s one-page checkout is now default)
• Ensuring mobile checkout is tested and frictionless

Want checkout customisation or Shopify Plus features? Our Shopify development team handles checkout builds from basic branding to full Plus customisation. Get a free consultation or view our work.