The Usabilla Android SDK by Claudio Semeraro interacts with the API to integrate feedback features into applications. Available manual instructions and Gradle instructions. An integration guide shows the step by step process to start an activity with the SDK.
GoodGuide is a service that we have been using as a family for a while. It attempts to analyze a product holistically & scientifically to produce a simple 1 to 10 rating of its "goodness." I am personally satisfied to see that the GoodGuide API will share this data with the world.
Anyone who runs an app these days has no doubt attempted to handle all customer service through email. While this may be a great way to interact with your customers, it can get difficult to track just how helpful your email help is. That's where Nicereply and its Nicereply API can help. And it even has a brand new example app, the product of a little recent criticism.