2 weeks ago, PSR-7 was finally accepted. It is an absolutely huge step towards framework interoperability. At last, we can build Middlewares, with applications that share a common domain side-by-side. This code snippet is from Zend Stratigility, a middleware system based on PSR-7: $app->pipe('/api', $apiMiddleware); $app->pipe('/docs', $apiDocMiddleware); $app->pipe('/files', $filesMiddleware); It