The DHL PHP library by Al-Fallouji Bashar offers to interact with the API services in XML such as shipment and courier pickup, logistics, and tracking time. These features could be useful to integrate into websites, applications, and even processing systems. On GitHub, Bashar has included examples to get quotations from a shipment, display a PDF label, and request a shipment.
Printful, a drop shipping service for custom print products and a product of the same team who created Startup Vitamins and BeHappy.me, has provided the Printful API that will allow people to easily integrate the functionality with their websites and applications. The service is specifically aimed at small and medium websites that want to offer print products, but don't want to handle the fulfillment and shipping of those products.
ShippingEasy consists of a cloud-based platform that allows online merchants to manage the processing and tracking of orders from a single interface. Merchants can integrate shipping information from multiple sites (e.g. eBay, personal site, physical warehouse, etc.) with the same interface and shop rates across various carrier lines. In addition to over ten existing integrations with e-commerce sites (e.g. Magento, eBay, Shopify, etc.), ShippingEasy offers a custom API that allows developers to incorporate the ShippingEasy platform into third party apps and sites.