Project Ara smartphone modules will sell through a Play Store-like marketplace, where developers can also list their own modular parts for sale, according to a Google executive.

Google announced Project Ara in October 2013. It's an effort that will allow people to assemble and replace parts (also called modules) of their Android smartphone as if it were a Lego set comprised of many pieces. Now we know where those modules will be available for purchase.

Paul Eremenko, director of Project Ara, announced during a Purdue University talk that consumers will be able to buy Project Ara modules through an online marketplace and that developers can use a Project Ara developer kit to create modules and sell them through the same marketplace.

"By following the Android model, we are creating a free and open platform. So, as Android is open source and freely available to anybody, the Ara MDK is free and open and available to anybody," Eremenko said.

He added: "And so anybody can create a module per the specifications of the developer’s kit and put it in the Ara module marketplace, which is analogous to the Google Play store, and sell directly to consumers."

Since last autumn, many reports and details have revealed that an Ara base skeleton running Android 5.0 Lollipop is expected to release in January 2015 for around $50. It isn't clear how soon after third-party modules will be available.

You can watch Eremenko’s full interview in the video above. The part about a Project Ara marketplace starts around 18:00.