Gowalla has announced the launch of its new Check in API. This is different than the Gowalla API, which was launched in February, which first let developers tap into Gowalla data for their apps.

"With today's release, we're expanding what's possible, enabling your applications to create check-ins on behalf of users," the company says. It utilizes OAuth 2.0 to do so.

The company gives developers the following guidelines for using the API:

• Encourage users of your application to check in at places they are actually located.
• Avoid incentives or game mechanics that reward checking in from distant locations.
• Never “auto check-in” a person without their explicit permission. This is seriously uncool.
• Encourage social interaction over bot-like behavior.
• Rapid, repeated check-ins with the intent to automate the location and swapping of items will not be tolerated.
• Go easy on the API. Cache data where you can, respond to error messages, and be thoughtful about your user experience.

The documentation is here.

The Check In API should help Gowalla continue to compete in an increasingly crowded check-in app space - a space that Google is starting to place more emphasis on and Facebook is expected to get more involved with.

In other check-in app-related news, Foursquare has opened up a new online store, where fans can purchase Foursquare merchandise and help Foursquare continue to boost its branding efforts.