Instagram tops 10,000 developers using Foursquare API

More than 10,000 developers behind some of the hottest apps on the iPhone (s AAPL), iPod Touch and Android (s GOOG)OS-based smartphones are using Foursquare’s application programming interface to tap into its location and places database, the company says. Foursquare launched its API in November 2009.

In a post published Friday on the Foursquare engineering blog, platform evangelist Akshay Patil writes:

We’ve seen some amazing apps and services built on our platform, which can power everything from simple web/SMS mash-ups hacked over a weekend, to month-long sweepstakes sending someone to space, to an innovative loyalty integration with American Express (which included seamless coupon redemption). Apps like Instagram, Foodspotting, and Venmo are using foursquare as their location layer. We’ve seen dogfood-distributing billboards,World of Fourcraft, and a New Year’s Eve party you could only get into by checking in. 10,000 incredible developers, all doing interesting things. That’s why we built this. And we can’t wait to see what else you come up with!

So what are these apps, and which ones are the most popular? According to a Foursquare spokesperson, the most popular third party app that uses Foursquare API for location-based check-ins is Instagram, followed by Tweetdeck, which was recently acquired by Twitter. Other top check-in apps include the likes of  Sonar, Hootsuite, GetGlue. and ironically, one-time Foursquare rival Gowalla.

The most popular unofficial versions of the Foursquare apps (aka not developed by Foursquare itself) are Foursquare for WebOS, 4th & Mayor, Foursquare for Nokia S40, Foursquare for Nokia’s Socially, and Foursquare for WP7, which recently underwent a total rebuild.

Foursquare reaching the 10,000 developer mark is just the latest in a series of positive news out of the New York City-based startup. Foursquare closed on $50 million in new funding in late June, and last week the company celebrated the opening of a new outpost in downtown San Francisco. The company is seeing heady growth both in the US and abroad — nearly 50 percent of Foursquare usage is in countries outside the US, CEO Dennis Crowley recently told GigaOM. With a solid API strategy and an evidently devoted third-party developer base, Foursquare’s growth is currently showing no signs of slowing down.