question

Separate app keys should be used for applications with different package names. Using the same app key for an application that is available through multiple Android app distribution channels is fine though.

Thanks for the reply. Are there no exception at all about this rule? (a different Key for every different package name) I was planning to use Amazon ads through MoPub mediation and some of my Apps (4-5) are using the same MoPub Ad Unit which would result of them also having the same Amazon application key. If the above is not possible I guess I will have to give up on the idea to use Amazon Ads :(

You may display ads only on your mobile properties, and only in compliance with the Mobile Ad Network Publisher Agreement. You will receive a unique application ID ("application key") for each of your mobile properties and such application key must only be used in connection with the display of ads on that mobile property. You may not use different application keys for mobile properties that are identical or substantially similar to each other (for example, two mobile properties with the same binary code, or versions 1.0 and 2.0 of the same mobile property), regardless of whether they have different names. More information can be found in the Mobile Ad Network Publisher Agreement here: https://developer.amazon.com/public/support/mobileads/publisher-agreement.html.