Android Educational Application Development

I'm looking to create an engaging and comprehensive educational application for the Android platform.

Key Features:
- User Authentication: The app should have a secure and intuitive user authentication system.
- In-app Purchases: The app will offer premium content and features through in-app purchases.
- Test Feature: The app should include a feature for quizzes and assessments.
- Online Book: The app will have an integrated online book for learners.

Ideal Skills:
- Android App Development: Proven experience in developing interactive and user-friendly Android applications is a must.
- In-app Purchases Integration: Familiarity with implementing secure and seamless in-app purchase systems.
- User Authentication Systems: Previous work with secure user authentication systems will be highly regarded.
- E-learning App Development: Experience in creating educational applications is a plus.

Please bid if you can deliver a high-quality, functional, and engaging educational app.