If you are just getting started with environment variables, I recommend reviewing your project's .gitignore file to ensure that your .env.development.local file is properly ignored.
Since .env.development.local is not committed, create a .env.example file containing the keys (but not the values) so other developers know what variables are required [3jop].
While it is generally bad practice to commit any secrets to version control, sometimes development variables still contain sensitive data (e.g., internal API tokens, database passwords for staging environments). .env.development.local provides a safe home for such values because it is never committed to the repository.
For example, a team's shared .env.development might contain: .env.development.local
Remember: commit the shared .env.development , ignore the local .env.development.local , and always respect the load order. Do this, and you will never again have the dreaded "but it works on my machine" argument over environment variables.
The resolution order from to lowest priority during local development looks like this:
: .env.local is loaded in all environments (except test), while .env.development.local is loaded only when NODE_ENV=development . If your server is not explicitly in development mode (or if NODE_ENV is misconfigured), .env.development.local may be ignored. Use .env.local for truly universal local overrides, and .env.development.local for overrides that should apply only during development. If you are just getting started with environment
The .env.development.local file is a powerful tool for creating a tailored, secure development environment. By allowing developers to customize their local setups without risking the exposure of secrets or disrupting the shared codebase, it ensures that the development workflow remains both flexible and robust.
API_BASE_URL=http://localhost:3001/mock-api
: Remember that variables prefixed with NEXT_PUBLIC_ or REACT_APP_ will be accessible in the browser. Do not put highly sensitive server-side secrets in these specific public variables. The resolution order from to lowest priority during
Frameworks like Next.js follow a specific loading order. When you run your development server, the configuration is loaded in this order, with later files overriding earlier ones: .env (Default for all environments) .env.development (Development specific) .env.local (Local overrides for all environments)
In a collaborative development ecosystem, applications need to change behavior based on where they run (e.g., local machines, staging servers, production environments). Instead of hardcoding these values into the source code, developers utilize dotenv patterns to inject configuration details at runtime.
Environment files, commonly known as .env files, have become a standard practice in software development for storing environment-specific configuration variables. These files contain key-value pairs that define settings for an application, such as database connections, API keys, and other sensitive information. The use of .env files allows developers to decouple configuration from code, making it easier to manage and maintain.
(Local developer specific, loads across all environments except testing)
The filename .env.development.local is broken down by its structural hierarchy: