On-Demand App Bug Fixes Needed

I'm seeking an experienced developer to address several critical issues in my on-demand application. The app is currently experiencing crashes, slow performance, and incorrect functionality across both iOS and Android platforms. These issues are particularly affecting the Login/Signup, User Dashboard, and Payment Gateway sections.

Key Requirements:
- Diagnose and fix app crashes on both iOS and Android
- Improve app performance to ensure smooth operation
- Correct functionality issues in key sections: Login/Signup, User Dashboard, and Payment Gateway
- Conduct thorough testing to ensure stability and reliability

Ideal Skills and Experience:
- Proven experience in mobile app development and troubleshooting
- Expertise in both iOS and Android platforms
- Strong problem-solving skills and attention to detail
- Ability to work efficiently and communicate effectively

If you have the skills to enhance the performance and reliability of my app, I would love to hear from you.