PHP Code Review and Optimization

I'm seeking an experienced PHP developer to review and make my API backend code work.

Key requirements:
- Coding efficiency and implement improvements
- Identify and fix existing bugs
- No documentation available, so need to navigate and understand the codebase independently

Ideal Skills:
- Proficiency in Code Igniter PHP and API development
- Strong debugging and code optimization skills
- Experience working without documentation
- Ability to work on an hourly basis

Please provide your hourly rate and relevant experience.