Foursquare’s Cofounder Is Going Public (With His Personal API)

At Foursquare, Naveen Selvadurai learned that people make use of public data in surprising ways. Now he’s exposing his most intimate data through a personal API that is open for public scrutiny.

Foursquare’s Cofounder Is Going Public (With His Personal API)

On Sunday, Naveen Selvadurai woke up at 8:30. He exercised on the West Side Highway running path, and racked up 5,130 Nike Fuel Points over the course of the day. Then he shopped at the CB2 furniture store and the Apple Store in SoHo. His weight was 149 pounds, up two pounds from Saturday. (Hope he didn’t overindulge when he got a late dinner at Peix Bar de Mariscos in NoLIta.)


Selvadurai’s accounts haven’t been hacked, and he isn’t being tailed by the FBI. All of this data was made publicly available by Selvadurai himself. You’d expect a certain amount of oversharing from the cofounder of Foursquare, but he aspires to an even greater level of transparency: On Friday, he unveiled a “personal API” that shares data gleaned from Foursquare, all of his various fitness tracking devices, and even his bathroom scale.

“I’ve long been a follower of the quantified self,” he writes. He’s used FitBit, Jawbone up, Nike FuelBand, and Withings, which were all useful for deriving insights about his health. “It’s shown me that seasons have a lot to do with weight makeup and that I seem to have a something like a 10-pound range in how much I weigh,” he tells Fast Company.

Making all of this health data public seems like a natural next step to him. “We share our tweets and checkins and photos and music habits to a wide audience, so why not other types of behavior and habits as well?” he writes. But these fitness gadgets are all competing with each other, and they don’t play well together. Selvadurai longed for something akin to the open APIs (application programming interfaces) that allow other sites to easily pull data from Twitter and Facebook. He claims his personal API yields “a dataset that is a single repository and view of my body as opposed to various silos of data scattered across different services and devices.”

Anyone who wants TMI about Selvadurai’s personal life just needs to visit Provide a Twitter handle, and you can get an access token that lets you pull the raw data on Selvadurai’s sleep schedule, weight, number of steps taken, and locations visited. For example, his weigh-in from yesterday looks like this:

{“date”: “2013-06-02T13:14:13”, “id”: “51ac3827d8949f001182cba3”, “value”: 67.95}

Not pretty to look at, but it’d be relatively simple for anyone with some coding knowledge to create a web page or app that presents the data in any way they like. And that’s the point. “I’ve been curious what one might be able to do with such a resource,” he writes. “Will any of it be useful for research? Might one create apps on top of me? Or perhaps draw insights that I haven’t yet been able to see myself?”


Selvadurai says that he isn’t exactly sure what people will do with it. His experience at Foursquare showed him that people make use of public data in surprising ways. (Like the time someone turned his location info into a visualization of a round-the-world trip he took.) Maybe someone will take his personal API and produce a chart proving that his weight spikes every time he eats at Shake Shack (which he last visited on Friday evening). “My hope is that I’ll learn something about my thinking or my data that I hadn’t seen before,” he says.

There’s some speculation that Selvadurai, flush with cash from his Foursquare departure, may be thinking about his next startup. Is his personal API a prelude to a company that unifies and quantifies your health data?

“I just put it out there to start a conversation,” he insists.

About the author

Chris Baker's writing has appeared in Wired, Slate, Entertainment Weekly, Kill Screen, and Giant Robot.