PSR-4

PSR-4 is a PHP Standards Recommendation that defines an autoloading standard for PHP classes, interfaces, traits, and other structures. It specifies a mapping between a namespace prefix and a base directory, enabling automatic class loading without manual require statements. This standard improves code organization and simplifies dependency management in PHP applications.

Also known as: PSR4, PHP-FIG PSR-4, PHP Standard Recommendation 4, Autoloading Standard, PSR 4

Why learn PSR-4?

Developers should learn and use PSR-4 when building modern PHP applications to ensure consistent and efficient autoloading, which is essential for frameworks like Laravel, Symfony, and Composer-based projects. It eliminates the need for manual file includes, reduces boilerplate code, and facilitates better project structure by aligning namespaces with directory paths, making code more maintainable and scalable.

Learning Resources

• docs: PHP-FIG PSR-4 Specification
• docs: Composer Autoloading Documentation
• tutorial: PHP Namespaces and Autoloading Tutorial
• video: Laracasts: Autoloading in PHP