You can do so to some extent in PHP. I'll wait for the PHP has rep to slow down.... In PHP, there is Framework Interior Group that created a few standards to w

You can do so to some extent in PHP. I'll wait for the PHP has rep to slow down.... In PHP, there is Framework Interior Group that created a few standards to which many frameworks implement their components. The interfaces are designed by FIG, and frameworks implement them (or rather, use libraries that implement them). Containers, HTTP message objects, request handlers, middleware, caches, they all can be interchanged if they implement these interfaces. Frameworks can now give the choice to the user to pick their own preferred libraries. There is Laravel, which is on the far end of opinionated frameworks, but Symfony andnSlim for example provided a lot of flexibility.