Pharmacy chain Walgreens, which already has one of the most popular mobile health apps out there, has released an application programming interface (API) so software developers can build the company's prescription scanning and refilling technology into their own apps. The functionality already is in drug information app PocketPharmacist and newly launched personal health record Healthspek, according to Deerfield, Ill.-based Walgreens.

The basic Walgreens app is widely used for finding retail locations, refilling prescriptions by scanning bar codes, setting personal medication reminders, looking up medication information, ordering photographic services and making appointments at in-store Take Care Health System clinics. Partners on some of those features include Epocrates and Aetna's iTriage.

"[Mobile apps] are just one way for us to interact with our customers. And we woke up to the fact that it may actually be even more lucrative to take that connectivity and open it up as an SDK, an API to third-party developers," Abhi Dhar, group vice president and CTO for the e-commerce division of Walgreens, tells MobiHealthNews.

"We have a rather popular mobile app, but in addition to that we want to offer the creativity of the developer community," Dhar adds.

Dhar says that more than 40 percent of Walgreens online refill requests now come from the app. "You have your pill bottle, you take your smartphone, you scan the barcode, you select your store, and you're done. You get a text that your prescription is ready. And our customers have voted with their downloads," he explains. (Correction: An earlier version of this article stated 40 percent of "refill requests" instead of "online refill requests".)

The Android version of the Walgreens mobile app has been downloaded between 1 million and 5 million times from Google Play, and the app enjoys an average rating of 4.3 out of 5 from Android users. While Apple does not disclose App Store download volume, Walgreens apps for iPhone and iPad have similarly high ratings.

Walgreens said nearly two years ago that more than 1 million people had signed up to receive texts when their prescriptions are ready.

Mobile is part of the chain's strategy to drive more traffic into its more than 8,000 U.S. stores.

"From our point of view, we have always maintained that our ubiquitous presence in terms of our retail stores is a critical part of the value proposition that we bring to America. We have always thought of mobile as a bridge across that channel," Dhar says. "Philosophically, what we've done is we've used mobile as a way to bridge a transaction that starts in one media and ends in another."

MobiHealthNews writer Jonah Comstock contributed to this story.