Comprehensive Event Management Mobile Application

I need a proficient app developer a (proof of concept) to construct a comprehensive event management app for both Android and iOS platforms.

Key Features Required:

- Account Login: The application must support user interaction through a secured account login system.

- Calendar Integration: The app should feature a calendar integration system for scheduling and tracking events efficiently.

- Attendee Registration: I want an easy-to-navigate system for attendee registration within the app.

- In-App Notifications: A vital feature of this app is a consistent and reliable in-app notification system to alert users about event updates.

- Chatrooms

Ideal Experience and Skills:

- Proven experience in developing both iOS and Android applications
- Expertise in user interface and experience design
- Substantial knowledge in building secure login systems
- Proficiency in integrating calendar functionality in applications
- Experience in developing attendee registration systems
- Capability to establish efficient in-app notification features.

This can lead to a full time job to develop a whole application.