Symfony is a PHP web application framework and a set of reusable PHP components/libraries. It was published as free software on October 18, 2005 and released under the MIT license. Symfony Components are a set of decoupled and reusable PHP libraries. Battle-tested in thousands of projects and downloaded billions of times, they've become the standard foundation on which the best PHP applications are built on. You can use any of these components in your own applications independently from the Symfony Framework.