Photobucket is introducing an API that will allow external developers to create applications that include content and functions from the photo- and video-sharing website.

Photobucket, which is owned by News Corp. and as such is a sister company to MySpace, has had an API (application programming interface), but it was available only to developers that Photobucket hand-picked and worked with individually.

It is now opening its platform widely to third-party developers, who can sign up for the API at the new developer site and get started coding soon after, said Photobucket President Alex Welch.

"We want to extend Photobucket's relevance for our users," Welch said.

Most of the photos and clips hosted by Photobucket are displayed in other sites, like MySpace and Facebook, and Welch expects that will also be the case with the applications built using its API.

Beyond other sites, Welch expects that developers will also use the API to create Photobucket applications for computers, mobile devices, cameras, set-top boxes and other consumer electronic systems.

The API will expose about 50 Photobucket functions, including video uploading, obtaining metadata about an image, editing photos, creating and accessing albums, and searching for content.

Photobucket will offer commercial and non-commercial flavours of the API. The commercial version is for applications that will be used massively and generate significant revenue. It requires a formal agreement between the developer and Photobucket, unlike the less formal, non-commercial version.

At launch, there will be about 20 applications built using the API by developers including Adobe, AOL, FotoFlexer, Intercasting, RockYou, Slide and Snapvine.

Some of those applications will be demonstrated at Photobucket's booth at this week's Web 2.0 Expo in San Francisco. The conference runs from Tuesday to Friday, but the expo floor opens Wednesday morning.

Developers and users can see Photobucket applications in its new Application Gallery site.

Photobucket has about 40 million unique users and hosts billions of photos, graphics, slide shows and video clips that are displayed in hundreds of thousands of sites.