Stamps.com is integrated with Sonicode's Mercury Web Shipping, a web application written entirely in PHP. Mercury installs easily on your own web server and eliminates shipping data entry with one‑click shipping that can be integrated into any existing shopping cart system. Mercury integrates with your existing ecommerce system in minutes, automatically retrieving the information from your shopping cart, eCommerce system, or CRM. Simply load Mercury and click the ship button and shipping label will be sent to your printer!