Cross-Platform Mobile App for E-Invitations

I'm looking for a cross-platform mobile application that can effectively manage electronic invitations. This app will primarily focus on invitation management for various types of events including parties and meetings.

Key Features:
- Comprehensive invitation management system
- QR code generation and scanning for each invitation
- RSVP tracking to keep track of responses
- Calendar integration for syncing with personal schedules
- Templates inserted by us for a consistent look and feel

Ideal Skills:
- Proficiency in cross-platform mobile app development
- Experience with QR code integration in apps
- Strong understanding of RSVP and calendar functionalities

Previous experience with similar projects would be a great advantage.