We are pleased to announce that the Yammer API developer platform has officially been launched. The API enables developers to build applications on top of Yammer and integrate Yammer into users’ existing tools and workflows.

With the release of the API, Yammer users should soon expect to have many of the same applications already available to users of other services such as Twitter.

In fact, Seesmic, developer of the popular desktop client, twhirl, has already announced that it would use the API to add Yammer support in the coming weeks. This will allow twhirl users to post status updates to either Yammer or Twitter from a single place.

The API will also facilitate the development of new productivity tools and the integration of Yammer with project management systems like Trac.

Yammer’s API offers much of the functionality available to users through a web browser. This includes access not just to posting messages and reading feeds but also to Yammer’s unique features such as tags, threaded discussions, and a company directory.

The API mirrors the security settings on the Yammer website. It supports SSL, and network administrators can block access to the API if the user tries to log in from outside the company’s IP range.

Network administrators can also simply turn off the API for their network if they do not want to permit third-party applications.

The coming weeks should prove to be very exciting as developers start to release applications built with the Yammer API.

For more information about the Yammer API, please visit the Yammer API page.