Plenty of apps let you share items with friends via Facebook, Twitter, and e-mail, but it’s still difficult to instantly share content within apps — for example, a cool new restaurant on Yelp’s app — across mobile devices.

Kik, maker of a popular mobile messaging app, aims to change that with its new API, which allows developers to quickly implement mobile content sharing within their apps to any of Kik’s 6 million registered users.

The API also lets you refer friends to a specific point in apps. For example, it could be used to point friends to a specific song you discovered on Shazam’s app. Even better, the API is platform agnostic, allowing you to share between iOS and Android devices seamlessly.

Kik’s app launched last year and saw explosive growth from users who were hungry for a fast messaging alternative to texting. The company now sees 500 million messages a month across its mobile apps, CEO Ted Livingston told VentureBeat in an interview yesterday. Kik’s chat volume has been doubling every quarter.

Kik is also launching a new “Apps that Kik” section of its app to promote apps using its API.

“Part of what has made Kik Messenger such a success has been connecting people anywhere while keeping the app experience very fast and easy to use,” Livingston said in a statement today. “The launch of the API and the addition of the Apps That Kik discovery service provide an insanely simple solution to drive app adoption for developers.”

As Livingston explained it, developers need to add only five lines of code to implement the Kik API. When a user chooses to share something via Kik, the third-party app opens the Kik app on their phone to complete the message.

Kik is launching the API today with several companies, including Smiler and FileKicker. To take advantage of the feature, you’ll need to download the latest Kik apps on iOS and Android, which also went live today.