- PSR-1: Basic Coding Standard- Naming Conventions - Classes: - StudlyCaps- 1 2 3- class ClassName { // ... }- Methods: - camelCase- 1 2 3 4 5- class ClassName { public function methodName() { // ... } }- Constants: - UPPER_CASE_WITH_UNDERSCORES- 1 2 3- class ClassName { const CONSTANT_NAME = 'value'; }- PSR-2: Coding Style Guide- Coding Styling: - Indentation: 4 spaces(as the tab)
- Opening brances for new class: on the new line
- Control structure should be followed by: single space(if / else / while)
- Function structure should: not have space(after the function name)
 - 1 2 3 4 5 6 7 8 9 10 11- class ClassName { public function methodName($arg1, $arg2) { if ($arg1 === $arg2) { return true; } else { return false; } } }- PSR-4: Autoloading Standard- PSR-4 is a modern autoloading standard that simplifies the process of including PHP files in your codebase. It requires: - A one-to-one relationship between class names and file paths.
- Namespace declarations to match the directory structure.
 - 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18- // ------------------------------------------- // File: src/ExampleNamespace/ExampleClass.php namespace ExampleNamespace; class ExampleClass { // ... } // ------------------------------------------- // Usage of the ExampleClass.php File require 'vendor/autoload.php'; use ExampleNamespace\ExampleClass; $example = new ExampleClass();- Reference: https://reintech.io/blog/php-and-psr-standards-writing-clean-and-compatible-php-code 
- Indentation: