This book contains a collection of articles on Expressive, a PSR-7 microframework for building middleware applications in PHP. Middleware is an elegant way to write web applications as it allows you to write targeted, single-purpose code for interacting with an HTTP request in order to produce an HTTP response. PSR-7 and middleware represent the future of web development in PHP, from small to complex enterprise projects. This book will help you get started using Expressive.