The interview process was bollocks and useless in the end. As someone else mentioned you either need to do a task, or send a project and describe where you used a dependency injection(singleton where you pass class to be initialized, that's what it is in their repo). I send the project since I already have one, and describe it accordingly. What I receive was a copy-paste about things that I did wrong.: 1. I used global variables, and I didn't(except of WP global variables, but every plugin uses that), 2. I have missing parameters type. Well, I used 2 static analyzers while developing, Psalm and Phan. Not a function was having parameter missing. Also in terms of JavaScript I used TypeScript with strict type, so of course not something there either with parameters type missing. 3. Missing exceptions. As above, with 2 static analyzers, all exceptions were caught. 4. I have empty files, yes, I have an empty index.php file which is used as empty to defend against a type of security attack. Even WP uses it, and it's best practice to use it.