Check your team, look up player stats and see the league's latest transactions, all from Yahoo's latest API. Fantasy baseball and football are both supported now, with options for hockey and basketball expected in time for their seasons. And the API supports OAuth, so developers could create new interfaces to almost every feature of Yahoo Fantasy Sports.

David Geller, Director of Fantasy Sports, said it's part of Yahoo's open strategy to make data available to developers. Some have already written homegrown methods of accessing the data, which means scraping the site. This API provides an official, supported way that is much easier for developers. Like other Yahoo APIs, Fantasy sports data is being made available via Yahoo Query Language (YQL), as well as a web service. See our Fantasy Sports API profile for more information.

The tools Yahoo is providing go beyond team and league adjustments. Developers can also access data for the current and previous season player statistics. In combination, this allows for applications that can provide fantasy owners with detailed analysis of their teams. Some potential uses for the API:

Projections for the league--who will win based on previous data?

Lineup analyzer--which player should I sub in to get better results?

Alerts for owners--does a player have a bye this week? Is a player injured?

An API like this has been requested as far back as 2007, with a mention on then-Yahoo employee Jeremy Zawodny's blog asking for web services ideas. Another commenter re-iterated the request when Yahoo announced its open strategy. Geller said it's been on the internal list for some time, but that recent deals with data providers have made it possible.

As with many APIs, the new fantasy sports platform is only available for non-commercial use. That is both good and bad news for users. The good news is that anything developers create will be available for free. The bad news is that developers won't be incentivized to create powerful tools for which users might pay. To address this downside, Geller said Yahoo is working toward a program where developers could, for a fee, upgrade their license to allow commercial use.

Update: A couple people in the comments have pointed out that MyFantasyLeague has an API. In fact, we have a profile of it. Nevertheless, none of Yahoo's competitors have an API, so I stand by the spirit of my headline.