In-App Purchase Integration for Both Platforms

I need an experienced developer to integrate in-app purchases for both Android and iOS platforms.

Here's what needs to be done:

Google Play Billing Integration
- Configure in-app products on Google Play Console.
- Integrate in-app purchase logic (e.g., consumable/non-consumable).
- Perform sandbox testing with internal team license testers.
- Deliver test APK and implementation documentation.

Apple IAP / Apple Pay Integration
- Setup products in App Store Connect.
- Integrate Apple IAP and Apple Pay (if applicable).
- Conduct sandbox testing with internal team license testers and provide test results/screenshots.

Minor Fixes, QA & UAT
- Resolve UI/UX or logic bugs reported by me.
- Conduct sanity testing and ensure app store compliance.
- Deliver final builds for both platforms.

Ideal Skills and Experience:
- Proven experience with Google Play Billing and Apple IAP/Apple Pay integration.
- Familiarity with sandbox testing processes.
- Strong attention to detail for QA & UAT.
- Documentation skills for a clear handover