Introducing Checkout Functions: Customize Every Checkout Step
Today we're releasing Checkout Functions — a powerful extensibility engine that lets merchants customize every step of the checkout process without writing code.
Rule-Based Logic
Build conditions like "cart subtotal > $100" and combine them with actions like "apply 10% discount" or "hide Cash on Delivery". The visual Rule Builder supports AND/OR logic, nested condition groups, and 12+ comparison operators.
Four Function Types
- Discount Calculate — Stack rule-based discounts on top of discount codes
- Shipping Filter & Sort — Hide, rename, and reorder shipping rates dynamically
- Payment Customization — Show or hide payment methods based on cart context
- Checkout Validate — Block checkout with a custom error for cart minimums, restricted items, or address rules
WASM Runtime for Developers
Need more than rules? Write a WebAssembly function in any language that compiles to WASM. Upload it via the API and the wazero sandbox runs it with a 50ms timeout — safe, isolated, and fast.
Checkout Branding
The new Checkout Branding editor lets you match your checkout to your brand: set primary colors, button styles, corner radius, and typography without touching code.
Extension Points
App developers can now register UI extensions at 8 checkout points — inject banners, custom fields, or loyalty widgets using our Remote UI component system.