Overview

I built and shipped a promotion code copy widget that enables customers to quickly copy discount codes and apply them during checkout to receive Prime Day discounts.

The widget was designed to be embedded across multiple merchant surfaces and marketplaces with minimal integration effort.
It was implemented using Vanilla JavaScript and delivered via iframe to ensure isolation, safety, and compatibility with Shopify templates.

The solution scaled to 3.5 million users within a two-week Prime Day window in July 2023 while maintaining high performance and reliability under peak traffic.