Shopify

Shopify’s discount editor will take a percentage or a fixed amount. It will not take “20% off, up to $50.” That is the whole reason Pricelid exists. The discount still lives in Shopify. The app stores the rule as JSON on the discount metafield, and a Shopify Function reads it while the cart is being priced. No theme edits. If the discount is not an order discount, or the metafield is missing, the Function returns no operations and checkout moves on. ...

Shopify Plus checkout will not let a theme hide Cash on Delivery. Payment and delivery customizations are Shopify Functions. Checkout Rules Pro stores the rules as JSON on a metafield and lets the Function read them at checkout. No theme code. No metafield, no operations. Payment methods Each rule names a method and an action. The Function lowercases the name and looks for a payment method whose name contains it. “Cash on Delivery” matches a hide rule for “cash on delivery.” ...

Some products are one pile of stock wearing several variant names. Shopify will happily track each variant on its own. Sell one, and the siblings still say they have the old count. Recount Kit treats those variants as a pool and lets Shopify stay the source of truth. The webhook Shopify sends inventory_levels/update when available quantity changes at a location. The handler turns the numeric ids into inventory-item and location gids, then looks for a pool member at that shop and location. ...