MULTI-STEP VALIDATION OF CONTENT ITEMS BASED ON DYNAMIC PUBLISHER REQUIREMENTS

A content item generation system which implements techniques for selecting and identifying content items to return in response to a request is described. For example, the content item generation system may separate requirements included with a request into first and second sets of requirements. The first set of requirements may be used to identify which content items or content item campaigns may be suitable to respond to the request. The second set of requirements may be used to determine whether items associated with the selected content items or content item campaigns correspond to technical requirements specified in the request.