Ever since the very successful Yahoo! Hack Day last fall there's been rumors about an API for Yahoo! Mail, the leading web mail service with over a quarter-billion users. And today it's official: the Yahoo! team announced the Yahoo! Mail API.
You can see our new Yahoo! Mail API profile here.
Earlier today I spoke with Chad Dickerson, Head of the Yahoo! Developer Network, and John Kremer, VP Yahoo! Mail, who point out that they're leading way here -- none of the other major platform vendors offer an official API like this yet. As is often the case with new APIs, they're looking for developers to innovate in ways they cannot predict: think utility functions like email backup or synchronization, enhanced local desktop client functions, widgets, or more playful applications like the Yahoo! Mail Flickr Postcard.
The API will allow applications to compose and send messages, work with mailboxes, etc. Keep in mind that the amount of functionality available to the API varies by the level of the user account being accessed. So a free account is limited to listing folders and messages while a premium account user has no restrictions. The Mail API leverages other Yahoo! developer services like the Yahoo! BBAuth API to credential the user. The core service is SOAP-based, but conveniently also supports a lighter-weight JSON-RPC implementation. Oh yes, while they make the API as simple as they can, email's inherently more complex than say bookmarks, thus the API docs PDF is over 100 pages.
This API release also adds another variant to the revenue models for mashup developers: referral commissions. For a trial period Yahoo! Mail is offering a $10 commission for every new Yahoo! Plus Mail account referred by developers.
They'll be showcasing examples over in the new Mail category over at the Yahoo! Gallery and we'll be listing them here as well.