Symfony is a set of PHP Components, a Web Application framework, a Philosophy, and a Community — all working together in harmony.
It also has a very good performance and an excellent cache system. It also has a cascading configuration system called YAML without forgetting the back-office generators and a module launcher. Its architecture is so flexible that it becomes possible to create and use plugins

The benefits of using this framework
It was created in order to easily integrate with an ORM which facilitates the object persistence of the databases. Symfony is also a multi-language framework with a more simplified and easier to use version. It also has a system that aims to improve the performance and efficiency of your website. It also includes several bundles or plugins. This framework has a strong evolution capacity and has a very large community of more than 300,000 symphony developers in 120 different countries. He also owns the R & D Labs which continuously distributes new versions of Sensio labs. Symfony can also provide a command line interface to improve productivity by creating a highly efficient and modifiable database at will.

Symfony 4: A new way to develop applications

A Better Symfony
Symfony 4 represents a rethinking of its ideas and features from the ground up to match the industry practices: application bundles are gone, config parameters are now environment variables, the application directory structure is easier to navigate and hundreds of other small improvements that will make you love Symfony.
The result is less Symfony concepts and more standard practices. Easier to learn, easier to configure, easier to install and deploy and easier to master. Simple, powerful, amazing!

Smooth Upgrade
Thanks to our unrivalled Backward Compatibility Promise, upgrading your existing applications to Symfony 4 will be a smooth experience. First, upgrade to Symfony 3.4, which provides total compatibility with any Symfony 3.x version. Then fix any reported depreciation and you are ready to upgrade instantly to Symfony 4.

Auto-registered & auto-wired services
Symfony 4 brings features that are designed to automate configuration to make the development easier and faster too.