The Pingen API allows sending postal letters online. Pingen is a web-based Hybrid Mail service that provides print, package, stamp, and post services. Recipients can receive letters in the mail from their senders who can validate documents, print envelopes, and track and trace their mail from Pingen.
The following is a list of how-to and tutorial content that matched your search term. ProgrammableWeb's how-to content comes from two sources; full-blown tutorials that we publish ourselves and other highly relevant tutorials that we find elsewhere on the Web. This list represents on combination of both tutorial types and if you go to ProgrammableWeb's API University, you'll not only be able to find more, they are organized based on your role (API providers or developers who consumes APIs). If you know of a tutorial that would be of interest to the ProgrammableWeb community, we'd like to know about it. Be sure to check our guidelines for making contributions to ProgrammableWeb.