Cross-Platform Wellness App Development

I'm looking for a skilled mobile app developer to create a wellness app for both iOS and Android platforms. The app should primarily focus on activity tracking.

Key Requirements:
- Develop a cross-platform wellness app (iOS and Android).
- Implement robust activity tracking features.

Ideal Skills and Experience:
- Proven experience in mobile app development for both iOS and Android.
- Strong expertise in activity tracking functionalities.
- Familiarity with wellness app trends and user interface design.
- Ability to deliver within budget constraints.

Please provide a portfolio showcasing similar projects.