API development best practices refer to guidelines that ensure the creation of efficient, secure, and user-friendly Application Programming Interfaces (APIs). These practices include designing for usability, maintaining proper documentation, ensuring security measures, employing version control, and consistently testing APIs. By adhering to these principles, developers can create APIs that are robust and scalable, making them easier for other developers to use and integrate. This leads to improved collaboration, innovation, and a better overall user experience across applications.