A Click2Mail API (application programming interface) is a set of tools used to produce an interface between Click2Mail and your website or application. Through an API, your system can do just about anything Click2Mail can: Produce and print postcards, notecards, letters, booklets, and brochures Automatically post and mail through the United States Postal Service using First-Class Mail, Non-profit Mail, Standard Mail, Priority Mail Plus, Priority Mail Express, Certified Mail, and Every Door Direct Mail Print in bulk and ship to one or more destinations Batch process mailings, manage mailing lists, administer accounts, print variable data, track mailings, verify addresses, and so on Do it all with one or one million pieces