In this episode, learners discover how to add custom validation in Sylius using the Symfony Validator component. We demonstrate how to implement validation rules for the Brand entity to prevent issues caused by empty or duplicate fields. Instead of annotations, validation is configured using XML files for better structure and flexibility.
We also cover how to provide translated error messages, apply validation groups depending on context (admin form vs API), and use Symfony’s built-in UniqueEntity validator. The episode walks through creating custom validation constraints, such as enforcing specific brand names based on brand type.
By the end, developers will be able to build flexible, context-aware validation systems that improve data consistency and user experience across their Sylius applications.