vlucasphpdotenv

vlucas/phpdotenv is a lightweight PHP library used to load environment variables from a .env file into the application’s environment. It was created by Vincent Lucas and is maintained as part of the Packagist ecosystem. The project is hosted on GitHub and allows developers to manage application configuration in a simple, human‑readable format that can be version controlled and overridden in production.

The primary function of phpdotenv is to read a .env file located at the project root, parse its contents, and populate the $_ENV and $_SERVER superglobals as well as the getenv() system. It supports syntaxes such as KEY=value, KEY="quoted value", and KEY='single quoted value', along with line comments prefixed by a hash. The library also handles comments and blank lines gracefully, and it includes optional auto‑casting of values that look like booleans, integers, floats, or strings, depending on the configuration.

To use the library, developers typically install it via Composer: composer require vlucas/phpdotenv. After installation, the application bootstrap file calls Dotenv::createImmutable(dirname(__DIR__))->load() or Dotenv::createUnsafeMutable(dirname(__DIR__)) to load variables. The "immutable" variant prevents variables that have already been set from being overwritten, which is a security feature that encourages proper configuration management.

Version compatibility remains stable across PHP 7.1 and newer, and the package has built-in support for the newest PHP releases through Continuous Integration tests. The library’s license is MIT, making it free to use in open‑source and commercial projects. Many popular PHP frameworks, such as Laravel, Symfony, and CodeIgniter, have integrated phpdotenv or provide support for its use, and it is also employed in containerized deployments where environment variables are crucial.