.env.development Today

: It keeps development-only logic out of the main code and prevents development settings from accidentally leaking into staging or production. Critical Considerations

Here is the golden rule: A user can open DevTools and see your REACT_APP_ variables. Never, ever put an admin password, database URI, or private key in a frontend .env.development file. Use a backend proxy instead. .env.development

Elias leaned back, satisfied. But in his exhaustion, he decided to do one final "clean up." He opened a new file to share with his collaborator, Sarah. He wanted to show her the : It keeps development-only logic out of the

FRONTEND_URL=http://localhost:3000

API_BASE_URL=http://localhost:5000/api DB_CONNECTION_STRING=mongodb://localhost:27017/my_dev_db # Mock/Test Credentials ever put an admin password

Both tools have built-in support.