Hardcoding API keys, endpoints, and configuration values directly in your React code creates security risks and makes switching between development and production environments difficult. With over 12 years of React development experience since 2014 and as the creator of CoreUI, I’ve configured environment variables for countless production applications. React supports environment variables through .env files that are loaded at build time, with variables prefixed with REACT_APP_ automatically exposed to your application. This approach keeps sensitive data out of version control and allows different configurations per environment.