Treat this file as ephemeral; it can be deleted and recreated without affecting the application's ability to run in production.
.env.development.local is a file used to store environment variables that are intended to be loaded during local development (when running npm start or npm run dev ).
Different frameworks handle and expose these variables to your frontend code using specific prefixes to prevent accidental security exposure.
// Load base .env dotenv.config( path: path.resolve(process.cwd(), '.env') );
: Use it for settings that only apply to your individual machine, such as a local database password or a personal API key that shouldn't be shared with the rest of the team. : Because it contains sensitive local data, it must never be committed to version control (Git). Ensure it is listed in your .gitignore Comparison and Load Order When running your application in development mode ( NODE_ENV=development .env.development.local
By strictly adhering to the rule that all .local files are ignored by Git, development teams gain two critical advantages: security, by keeping secrets out of the codebase, and hygiene, by keeping the repository free of conflicting, machine-specific configurations.
Now, let's focus on .env.development.local . This file is a variant of the .env file, specifically designed for development environments. The .development.local suffix indicates that this file contains environment variable settings for a local development environment.
API_URL=https://dev.api.com DEBUG=true
has been updated with any new keys you added to your local file so other team members know they need to provide their own values. Treat this file as ephemeral; it can be
To get the most out of .env.development.local , follow these best practices:
To understand its exact purpose, it helps to break down its name:
# --- DATABASE CONFIGURATION --- # Local database connection (different from staging/production) DATABASE_URL="postgresql://user:password@localhost:5432/my_dev_db" # --- API KEYS & SECRETS --- # Personal API keys for local testing STRIPE_SECRET_KEY="sk_test_51Mz..." AWS_SECRET_ACCESS_KEY="your-local-dev-key" AUTH_SECRET="a-very-long-random-string-for-local-auth" # --- APPLICATION SETTINGS --- # Local API endpoint overrides NEXT_PUBLIC_API_URL="http://localhost:4000/api" DEBUG=true # --- THIRD-PARTY SERVICES --- # Local-only sandbox credentials MAILTRAP_USER="your_mailtrap_user" MAILTRAP_PASS="your_mailtrap_password" Use code with caution. Copied to clipboard Key Rules for This File
The Role of .env.development.local in Modern Web Development // Load base
export const env = parsedEnv.data;
However, the rules differ for code that runs in a user's browser (client-side JavaScript). The framework you're using determines which variables are made available to the front end.
The primary reason for the existence of any .local file is security. Standard practice dictates that .env.development.local should always be included in a project's .gitignore file. This prevents developers from accidentally committing sensitive "secrets"—such as personal API keys, local database passwords, or private authentication tokens—to version control systems like GitHub.