OTP Integration for Android Java App

I'm seeking an experienced Android developer to integrate a One-Time Password (OTP) system into my Java-based Android app. The main purpose of this integration is to enhance the security of the app. The specific type of OTP and service provider can be decided in consultation with the developer based on their expertise.

Key Requirements:
- Proficiency in Java and Android development
- Experience with OTP integration
- Knowledge of various OTP service providers (e.g., Twilio, Firebase, AWS SNS)
- Ability to implement reliable and secure OTP functionality