Comprehensive RESTful API for Salon App

I'm looking for a proficient developer to create a robust RESTful API for my salon application. This API should be compatible with both mobile and web platforms.

Core Functionalities:
- User Authentication: The API should facilitate secure login and registration processes for different user roles.
- Appointment Scheduling: It should manage and streamline booking systems for clients and salon staff.
- Service Management: The API must handle various services offered by the salon and their corresponding details.

User Roles:
The API needs to cater to three user roles efficiently:
- Customers: Regular users who will book appointments and select services.
- Salon Staff: Employees of the salon who will manage appointments and provide services.
- Administrators: Users with overarching control who will manage the entire application.

Ideal Skills and Experience:
- Expert in RESTful API development.
- Proficient in both mobile and web application integration.
- Prior experience working on salon or service-based application APIs is a plus.
- Strong understanding of user authentication and role-based access control.
- Excellent skills in appointment scheduling and service management systems.