.env.development

, your variables must often follow a specific prefix to be accessible in the browser: Create React App : Prefix with REACT_APP_ REACT_APP_API_URL : Prefix with VITE_API_URL Stack Overflow 3. Load the Variables Most modern frameworks automatically detect .env.development when you run commands like . For a standard Node.js project, you can use the dotenv package to load specific files manually: javascript // Load environment-specific file ).config({ path: process.env.NODE_ENV Use code with caution. Copied to clipboard 4. Implement the Feature in Code Access these variables via process.env to toggle features or change behavior dynamically. Stack Overflow Example Implementation: javascript apiUrl = process.env.REACT_APP_API_URL; // Feature toggle based on env variable (process.env.REACT_APP_ENABLE_BETA_UI === ) showBetaFeatures(); Use code with caution. Copied to clipboard 5. Best Practices

: In most frameworks, .env.local will override .env.development . If you need to customize a value just for your own machine, use .env.local instead of editing the shared development file. .env.development