Creating Python REST APIs with Flask, Connexion, and SQLAlchemy

API documentation is crucial for collaboration and usability, yet many developers avoid writing it because it doesn't affect code functionality. However, using tools like Connexion with Flask can streamline the process by allowing developers to create APIs and their documentation simultaneously through the OpenAPI specification. Connexion simplifies API development by mapping endpoints to Python functions directly in a YAML file, bypassing the need for traditional Flask route decorators. This approach is demonstrated by setting up a basic shipment API using Flask, Flask-SQLAlchemy for database modeling, and Marshmallow for schema handling. Connexion ensures that the API documentation is always in sync with the code, enhancing maintainability and usability. The setup involves configuring a SQLite database, creating a YAML file for API routes, and writing Python functions for various endpoints, with the finished API accessible through a user-friendly interface at the /ui route.