I need someone who has already worked with the PhonePe Business SDK to add its payment-gateway flow to my existing Android app. The build is ready for release; what’s missing is a smooth UPI checkout that complies with PhonePe’s latest documentation, handles checksum generation on my server, and returns reliable success / failure callbacks inside the app. You’ll receive the current source code as soon as we start so you can plug in the SDK, create the required backend endpoints, and test the full round-trip on a staging account before we push to production. I expect the updated APK plus the concise implementation notes (API keys masked) so that my in-house team can maintain the flow after go-live. If you’ve integrated PhonePe on Android before and can demonstrate at least one live build, this should be straightforward. Let me know your estimated turnaround and any clarifications you need.