Hello!
I’m creating an application that will allow users to make offline payments.
Here’s the scenario:
Suppose a user has no internet connection and creates an offline payment. Then, just after completing the offline payment, they close the application and, after that, gain access to the internet.
My question is: Will the user lose the offline payment data because they closed the app?
In this scenario, they only close the app (they don’t reset, sign out, or do anything like that).
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Based on the information you’ve provided, the following documentation will help answer your question:
Payment API: Process Online and In-Person Payments
In-App Payments SDK Overview
In-Person Payment Solutions
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No, the user will not lose the offline payment data. The Square Point of Sale application processes offline payments automatically when the device reconnects to the Internet. However, it’s important to note that payments might be declined if not processed within 24 hours.
This answer was reviewed by @Bryan-Square.
Let me see If I understood correctly…
The offline payment functionality are only available for POS devices.
Is it possible to allow offline payments in an iPhone device for example?
Yes, it is possible with iPhone with the Square app. 
Thanks for the answer!
So… An application that I’m creating for iOS cannot use the Square API to allow offline Payments?
I’m required to use the Square app?
At this time this is true. A custom application that uses Reader SDK isn’t able to take offline payments at this time. This is a very popular feature request and we hope to have more for you soon.
Thanks again Bryan!
Is it possible for me to send the user from my application to Square application (If they have the Square application installed and are logged in) in a way that they can perform the offline payment inside the Square iOS app and return to my application after?
Everything happening without internet connection.
Cool that this is possible!
Last question (that is actually the first of the topic)!
Suppose a user has no internet connection and creates an offline payment in the Square App. Then, just after completing the offline payment, they close the application (the Square application) and, after that, gain access to the internet.
My question is: Will the user lose the offline payment data because they closed the Square app?
In this scenario, they only close the app (they don’t delete, sign out, or do anything like that).