Mobile App OAuth Integration

I need a mobile application for both iOS and Android that connects to Microsoft Graph and Gmail OAuth. The app should be able to access, read, and manage the following elements:

- Emails
- Calendar events
- Contacts
- and all the rest :)

Ideal Skills and Experience:
- Experience with OAuth integration
- Proficiency in both iOS and Android development
- Familiarity with Microsoft Graph API and Gmail API
- Strong background in mobile app security

Looking for developers who can ensure secure and efficient data access.