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Comment by deanCommie | Hacker News Reader

> In order for Google Play to ensure a consistent purchase experience regardless of where the user purchases your product, you must acknowledge all purchases received through the Google Play Billing Library as soon as possible after granting entitlement to the user.

Can someone who understands this domain better explain why this exists?

A superficial reading of the text triggers thoughts of "fraud prevention", but the code the author uses to fix it is clearly one a fraudulent app can also easily include.

Other thoughts about preventing poor user experiences such as dark patterns to trigger accidental purchases, or bait-and-switch functionality with Fremium apps also don't seem to be prevented by this.

So what's going on?

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Play Billing 2.0 added the ability to purchase in-app items from outside of the application.

This ACK confirms that the application properly processed the notification and delivered the item to the user. Otherwise, Play assumes that the purchase was lost in the ether sometime before fulfillment (e.g. bug, the app crashed, etc.).

I assume that part of it is a psychologically-motivated desire to maintain a tight reward loop for Play purchasers, with no payment-processing delays.

How do you get that out of previous comments

Otherwise the item could only be available once purchase was confirmed.

How could it be available if the application didn't ACK that it received the purchase order and granted the item?

From the post, it sounds like the users receive the purchased item immediately but the app developer needs to confirm that the charge went through properly. Otherwise the funds are returned but the user keeps the purchased item.

Without acknowledging the purchase the money was refunded back to the people who purchased it. And the best thing was the dark theme would be activated even if the user got the money refunded.

I was confused too because it sounded like the developer had to log in and click something to acknowledge the purchases. But it’s the app that needs to acknowledge that it has unlocked its features for the user. Makes sense to me now.

My guess would be to prevent lost delivery of the "payment received" notification from impacting the purchaser.

So Google knows that you know that they paid, would be my guess.

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