This document introduces Shopify Scripts, which allow merchants to write sandboxed Ruby scripts that can mutate cart data and discounts. Examples shown include applying percentage discounts based on quantity, checking if a customer is a Shopify employee, and modifying template code to conditionally display original prices. Limitations of scripts include no network requests, one script at a time, and a 16,384 character limit. Resources provided include the open source engine, a demo store, the developers program, and sample scripts.