In this age of massive Composer’s library, it is impressive to know that we rely merely on a component name and a version number to decide on a dependency. And this is also true with frameworks or applications. In the Open Source world, checking the code’s description means reading it, and then fixing the errors as they pop up in the tests or the logs. It would be nice to have a more detailed description of our dependencies. Introducing the PDFF : PHP Document File Format. It describes all the OOP structures that we and static code analysis love, in machine readable format. Devised by versions, it list all the available elements and their constraints, such as visibility, extends, types and default values. By itself, it makes it easy to check if anything is changed in the code. By comparison, it gives a frame of description to identify what was added, changed and removed. And in the future, we may also include extra recommendations beyond the current PHP syntax.