Will also enable easier integration of GameCircle features.
Amazon is keen to encourage sales of its Kindle Fire and activity around its Appstore, which is why it launched the GameCircle platform in summer; a two-way tool that offers developers monetisation opportunities, while gamers have better ways to interact with each other.
Now, the online retailer has announced those developing with Unity will have access to free plugins for in-app purchasing and GameCircle APIs, enabling the developers to add the features to their titles.
Mike Frazzini, director of Amazon Games, said: "Every week millions of customers are playing GameCircle enabled games and are able to compare scores and compete against friends. We want to make it as easy as possible for developers to quickly integrate these features and our new, free plugins make it incredibly simple to do so for anyone using Unity."
David Helgason, CEO, Unity Technologies, added: "Amazon helped to change the way the world looks at the internet and retail. We're excited to see them bring their energy to games and especially games built with Unity."
"We recently integrated GameCircle into Temple Run using the GameCircle plugin for Unity. The process was very easy, and incredibly fast," said Keith Sheperd, founder and CEO of Imangi Studios, and creator of Temple Run. "What would have normally taken days to integrate only took a few hours and it was all very straight forward. We will definitely use the Unity plugin to add GameCircle and In-App Purchasing to our other games."