Firebase/Subparse Backend Database Development

I need an experienced developer to build a backend database using Firebase or Subparse. The database will primarily store product data, as well as essential user data such as personal information, login credentials, and activity logs.

Core functionalities required:
- Data storage and retrieval
- User authentication
- APIs for external services

Ideal skills and experience:
- Proficiency in Firebase or Subparse
- Strong background in database design and management
- Experience with user authentication protocols
- Ability to integrate APIs from external services

Please provide examples of similar projects you've completed.