The Custom Logic folder in the Administration menu consolidates Grids that are related to any custom code that is written for a particular environment. There are three types of Custom Logic available: Events, API, and Validation.
Prerequisites
Developing Custom Logic is intended for Administrators and an understanding of PHP language and syntax is required. You must also be aware of language compatibility for the version of PHP installed on the web server. For logic that requires querying other data, an understanding of SQL is necessary, particularly variants specific to your database platform.