I am developing an iOS app where users can withdraw their balance using Venmo. My app uses Firebase for backend services including user authentication and Firestore for database management.

Requirements:

Venmo Integration:

I need to implement a feature that allows users to withdraw their balance using Venmo.
Are there any specific APIs or SDKs recommended for integrating Venmo with Firebase?
Backend Implementation:

I need the backend code in JavaScript (Firebase Functions) to handle the withdrawal process.
The backend should securely handle the transaction and update the Firestore database accordingly.
Specific Help Needed:

Setting Up Venmo API:
How to set up the Venmo API to initiate and process withdrawals?
Firebase Functions Code:
A sample Firebase Function to handle the withdrawal process.
Best practices for ensuring secure and successful transactions.
Any guidance or sample code snippets would be highly appreciated. Thank you!