Use composer for dependency management of PHP files, NPM for javascript.
Testing Guidelines
Use BDD and behat/gerkin stories for testing
Code Style & Guidelines
Use design patterns and best practices where appropriate.
Prefer to not use a framework
Dependency Injection, OOP, etc.. are all to be used unless you have a valid/good reason not too.
Use traits for shared functionality amongst objects/classes.
Use attributes to define routes, command, event and query handlers, CQRS, event driven/domain driven development, w/ event sourcing. Prefer microservices or modular monoliths that run as services using OpenSwoole.
Documentation Guidelines
Comment any code that might not be readily apparent what it's for/does, as well as any work arounds.