Creating custom themes
Creating custom plugins
Rest Api (Headless)
WP-CLI
Wordpress as Service
ACF
Custom Fields
Woocommerce
Open LiteSpeed
CDN integration
Security, optimalization and caching
Object-oriented programming (OOP)
Design patterns
Dependency inversion and Dependency injection
KISS, SOLID, Clean Code (Robert Cecil Martin have printed ver) OOP vs FE
Databases
Data structures, architecture, managment system
Relational (MySQL) and no relational (Mongo)
Database normalization, indexing, caching, troubleshooting
Usage of different ORM ex. Doctrin with lazy loading
Patterns Active Record (small) vs Datamappers (corpo) Mysql Router
PHPUnit
I am aware that PHPUnit testing coverage is crucial but it is such a pain ;(
Code sniffers, Static Code Analyzer Tools (PHPStan, PHPCSFixer, Psalm, Rector, ...)
PSR standards (forced by PHPStorm)
declare (strict_types=1)
Composer:
Helpers
Guzzle and PHP-HTTP/Guzzle6-Adapter
Monolog
Carbon
Faker
PHP-DI
Firebase PHP-JWT
Ramsey/Uuid
PHP dotenv
SwiftMailer and PHPMailer
Symfony Yaml, Console
League helpers
Flysystem, CommonMark, Plates, CS, Flysystem-Aws-S3-V3