NelmioApiDocBundle is a Symfony bundle that allows you to generate a decent documentation for your APIs. The version 4.0 of the bundle have just been released providing OpenAPI 3.0 support. Migration guide is available from 3.x to 4.0 and from 2.x to 3.0. NelmioApiDocBundle is available under an MIT license. You can install it from composer using :
composer require nelmio/api-doc-bundle
Documentation is available here. Official repository : https://github.com/nelmio/NelmioApiDocBundle