Discount Engine

Overview

A discount engine evaluates promotions against a cart and applies the right discounts in the right order. Every major e-commerce platform has one built in — you should configure the platform's native system before considering custom code. This skill covers how to set up complex discount logic (percentage off, fixed amount, BOGO, tiered thresholds, conditional rules) on each platform, and when to use apps or plugins to extend native capabilities.

When to Use This Skill

• When building a promotions system for a new e-commerce store
• When adding coupon code support to an existing checkout flow
• When implementing tiered pricing (e.g., buy 3+ get 10% off, buy 10+ get 20% off)
• When creating automatic discounts that apply based on cart conditions
• When you need BOGO, bundle, or gift-with-purchase promotions

Core Instructions

Step 1: Determine the merchant's platform and choose the right tool