IOS/Android App Developer for In-App Payments

We are seeking an experienced Android app developer to integrate in-app payments into our existing application. The ideal candidate will have a strong understanding of mobile app development and payment gateway integration. You will be responsible for ensuring a smooth and secure payment process within the app. If you have experience with similar projects and can deliver reliable results, we would love to hear from you. Here's everything that goes into in app payment specifically: 1- Payment Integration (IAP) — setting up In-App Purchase for both iOS and Android, since Apple requires it for digital features like this 2- Promotion UI — a screen where users select duration (3-day or 7-day) and see pricing clearly before purchasing 3- Feed Priority Logic — backend changes so promoted posts/projects automatically rank at the top of the feed 4- Expiry Handling — automatic system to remove the "promoted" status once the duration ends, and return the post to normal ranking 5- Testing — making sure purchases process correctly, promotions expire on time, and there are no bugs in feed ordering This is essentially building a full mini payment + ranking system inside the app. Last but not least: attaching the payment plans list onto the website aswell.