EasyPost is an industry leading shipping label API that connects with over 25 domestic and international carriers
. Zentail connects with EasyPost instead of maintaining each carrier integration individually. EasyPost is free for Zentail customers (normally they charge $0.03 to $0.05 per label).
EasyPost allows you to connect your UPS, FedEx, etc. carrier accounts. For USPS the rates from EasyPost are the same exact rates offered by ShipStation and Stamps.com -- commercial plus pricing for everything except First Class which no longer offers commercial plus. When you use EasyPost's USPS offering, you're shipping on their Endicia account. If you require, you can have EasyPost connect your Endicia account but the rates will be the same so we recommend sticking with EasyPost's account.