Is there a way to embed Paypal in a webview passing parameters to it, and get response (success/fail) once the payment is done?
I haven’t tried it, but I would be surprised if Paypal allowed embedding it in an iFrame like that. It would probably block it since they typically recommend using an SDK to do this within apps (not possible in Adalo). I think other payment providers is on Adalo’s roadmap though.
What you might be able to do though is use something like Integromat to generate a contract though and then fulfill the payment that way, though I also doubt the app stores would take kindly to that method either.