Cross-Origin Resource Sharing (CORS) is a security feature implemented by web browsers that allows or restricts web pages to make requests to a different domain than the one that served the web page. [[Django]] provides a middleware for handling CORS, and [[React.js]] can be configured to handle CORS, ensuring seamless and secure communication between the frontend and backend. Django: - Install `django-cors-headers` via pip. - Configure CORS middleware and settings in `settings.py`. - Understand safe origins and how to configure them.