I could jump directly to the answer but before I do, theres a crucial question every seller needs to ask themselves - Do I need to integrate?
Integration is a buzzword. You should integrate only if it serves your business case well and you have the tech expertise to do so.
That being said, if you are sure about integration - Try Instamojo.com. The support and integration kit is supremely simple in nature and will allow you to start operating within minutes.
You can integrate Instamojo with your website, app or any online platform. Follow this link to see how:
https://support.instamojo.com/hc/en-us/articles/207761969-Website-Mobile-Application
Hope this helped!
Feel free to write to support@instamojo.com for further queries. Havent signed up yet? Try it for free now!
Instamojo has a simple, 2-minute onboarding process and gets you going in a jiffy!