Android app Developer with Java and Kotlin

I am looking for an Android app developer with experience in Java and Kotlin. The primary purpose of the app can vary, from a chat app to a healthcare app, and more. The client has provided complete designs for the app, and they require a payment gateway integration. The ideal candidate should have experience in developing Android apps with Java and Kotlin and should be familiar with integrating payment gateways. Additionally, knowledge of social media login and custom APIs would be a plus.