.env.development.local Jun 2026

The resulting process.env.DATABASE_NAME will be alices_dev_db because .env.development.local overrides the others.

Security is paramount when dealing with environment variables, and this is where understanding your framework's behavior is crucial.

While the system is powerful, it's easy to fall into common traps that can cause hard-to-debug issues.

To understand its name, let's break it down into its three components: .env.development.local

You forgot the framework-specific prefix (like REACT_APP_ or VITE_ ). Fix: Rename your variable in the file.

.env # Base: DATABASE_NAME=my_app .env.development # Dev: DATABASE_NAME=my_app_dev .env.development.local # Local dev: DATABASE_NAME=alices_dev_db

npm install dotenv-flow

: Use this file to set variables (like a local database password or a private API key) that should override general settings defined in .env.development Security & Privacy : This file is intended for your machine only. It should be added to your .gitignore

When you run your application locally in development mode, the application will use http://localhost:5000 because .env.development.local takes precedence. Why Use .env.development.local?

Next.js supports environment files but with a twist. It supports .env.development and .env.local , but officially .env.development.local is not a documented file. Next.js recommends using .env.local for all local overrides, regardless of mode. Always check your framework's documentation, as this behavior is not universal. The resulting process

Before you even create the file, ensure your version control system will not track it. Open your .gitignore file at the root of your project and add the following lines:

If you are currently setting up environment variables for a specific framework, let me know:

# .env.development.local DATABASE_URL="postgresql://myuser:mypassword@localhost:5432/myapp_dev" NEXT_PUBLIC_ANALYTICS_ID="G-DEV123ABC" To understand its name, let's break it down

.env.development.local file is used to store local-specific environment variable overrides that only apply during the development phase. It is commonly found in frameworks like Create React App Core Purpose & Best Practices Local Overrides

When your app runs in development, it loads environment files in a specific order. Files listed earlier (left to right) have higher priority and will override matching keys in files to their right: .env.development.local (Highest priority) .env.local .env.development (Lowest priority) Example Content The file follows a standard format. Here is how a typical .env.development.local might look: # Example overrides for local development only PORT=4000 DATABASE_URL= "postgres://localhost:5432/my_dev_db" API_SECRET= "your-private-local-key" DEBUG_MODE=true Use code with caution. Copied to clipboard Comparison Table Shared (Commited to Git)? Default values for all environments. Yes (often as .env.example .env.development Values specific to development. Yes, if they aren't secret. .env.development.local Local secrets/overrides for development. No (Add to .gitignore programmatically load this file in a specific framework like Node.js or React?