PHP Bug Fix and Performance Tuning

I'm seeking a skilled PHP developer to fix compatibility issues and enhance performance on my existing application.

Key Requirements:
- Fix existing bugs, particularly compatibility issues
- Improve database query efficiency
- Reduce page load time
- Optimize API response time

Ideal Skills and Experience:
- Strong proficiency in PHP
- Experience with performance tuning and debugging
- Familiarity with database optimization
- Knowledge of web application compatibility across different platforms

Looking for someone with a proven track record in similar projects. Please provide examples of previous work and relevant experience.