Cross-Platform Social Media App Development

I'm seeking an experienced app developer to create a social media application for both iOS and Android platforms.

Key features to include:
- User profiles
- Messaging system
- Content sharing

Ideal skills and experience:
- Proven track record in developing social media apps
- Expertise in cross-platform app development
- Strong UI/UX design skills
- Familiarity with database management and real-time messaging technologies
- Knowledge of content sharing protocols and security measures

Please provide a portfolio of similar projects.