In this chapter, we have covered valuable web API elements. We learned how to differentiate between types of web API users, and the authentication and methods provided to do so. We also learned how easy it is to create our own APIs with just a few lines of XML. We saw how the route definition allows for easy binding between what comes via an HTTP request to what executes in code, respecting the access list permissions in the process. The value of building APIs as part of our distributable modules lies in their extensibility. APIs force us to embrace the interface way of thinking, thus allowing others to use and extend our code easily and securely. The preference mechanism we introduced in previous chapters, through di.xml files, allows others to change the behavior behind the interface easily.

Moving forward, we are going to take a more thorough and rounded look at building and distributing our extensions via Composer and Packagist.