To integrate UPI SDK in you android app you have to partner with a bank which is offering this service. Only UPI enabled banks are allowed to act as PSP (Payment service Provider). Some banks which are offering this service are: Yes Bank, RBL, ICICI Bank, Axis Bank.
Once you have the SDK it's pretty much Plug n Play and will hardly require a day's work. Although the bank that is offering you the SDK will review the developed app to see if it matches their security standards.
It's difficult to find well documented files about how to implement the UPI integration on UPI's website, but below I am mentioning some of the links which you can refer to. Cross refer all documents, one document alone won't help:
You can't integrate, unless you are bank,
I am also investigating how to integrate UPI - API in app,
but unfortunately as of now its restricted to developers,
only bank can develop this app using
I am assuming you aren't asking to become a PSP by yourself as that would require a lot more than just integration(you'll have to be listed under RBI to become a PSP, etc.)
But your problem can be solved by becoming a merchant which will use a PSP in the user's mobile phone. Basically, you will create a URI and will send that as an intent. The PSP apps are given the guidelines to listen to the specific URI and hence, you can invoke the desired PSP app from the list(if you have many PSP apps installed).
The URI will contain the required information. The PSP app can get the details from the URI and the user can just confirm for the payment. The response is being sent to the calling app with the transaction Id and some info. You can use that to carry on with your app's flow.
You can create the URI in the following way:
and the intent can be created like:
Intent intent = new Intent(); intent.setData(Uri.parse(UPI)); Intent chooser = Intent.createChooser(intent, "Pay with..."); startActivityForResult(chooser, 1, null);
Listen to the PSP response in the
onActivityResult method of your activity.
Even I was looking into this integration but for PHP, you can have a look into the below open source project written by Ragunath Jawahar for android
And see if it could help you out with