Hi, (from Canada)
I’m building a new mobile Android app to open the Square Point of Sale application and process in-person payments using Square contactless card reader.
Everything works fine. I initiate transactions in the POS.
Once the transaction is initiated, if the user decides to walk away the app is going to wait for an action and disable the card reader at some point.
I would like to cancel the transaction after a certain amount of time.
Can you help ?
Thanks in advance.
You can set an autoReturn but that only works for completed payments. Otherwise there isn’t a cancel payment call that can be made. Also since it’s the app is seller facing there really shouldn’t be a situation where the seller walks away from checking out the customer. 
It’s intended for self service checkout Kiosk - So no seller next to the user.
What happens if I just restart the app after a certain period with no success payment. Is the transaction gonna be stuck and block further transactions ?
All I want to avoid is that the next user come and finds a screen different than the Homepage.
The Square app itself isn’t intended to be used as a self checkout kiosk. Point of Sale API allows developers to create any number of solutions leveraging Square hardware — including custom point of sale systems, line-busting mobile retail solutions and attended self-checkout kiosks.
Unfortunately, the Point of Sale API is not suitable for an unattended payment scenario, such as a vending machine or unattended kiosk. Please make sure that your payment terminal is only available during business hours and is within line-of-sight of employees at all times.
If you want to build a kiosk we recommend building with the Terminal API.
Very interesting.
I see that the Terminal API has a cancel terminal checkout request.
Thank you for the tip.
It’s just unfortunate that the square terminal is a little out of budget for us right now.
Thanks again for your help.
I’ll be sure to share this with the team.