Self-hosted apps that integrate with USPS

3 open-source, self-hostable projects list USPS as an integration.

• Spree CommerceSelf-hosted, open-source headless commerce platform with Store, Admin and Seller REST APIs, typed SDKs, a React admin and a Next.js storefront.
• OpenCartSelf-hosted, open-source PHP ecommerce platform: run your own online store with multi-store admin, unlimited products, payment and shipping modules.
• abantecart-srcAbanteCart is a self-hosted, open-source PHP eCommerce platform for online stores with no licensing fees, offering multi-store management and extensions marketplace.