Price Rules Engine

Overview

A price rules engine lets you define multiple concurrent promotions — site-wide sales, coupon codes, loyalty discounts — and apply them to a cart in a predictable, controlled order. The key concerns are: which rules apply to which products, which rules can stack with others, and what happens when multiple rules target the same item. Every major platform has some form of this built in; the gap is usually in advanced stacking control and customer-segment targeting.

When to Use This Skill

• When you have multiple concurrent promotions (site-wide sale + coupon + loyalty discount) and need deterministic stacking behavior
• When marketing needs to create complex promotions (e.g., "20% off all shoes except Nike, for Gold loyalty members") without engineering involvement
• When migrating from hardcoded promotional logic scattered across the codebase to a data-driven rule system
• When building a promotion scheduler that activates and deactivates rules at configured times
• When you need an audit log that shows exactly which rules were applied and why for customer service queries

Core Instructions

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