This endpoint retrieves all custom field definitions configured for the organization.

The response includes custom fields for different entities:

• users → Custom fields defined for user entities
• applications → Custom fields defined for application entities
• vendors → Custom fields defined for vendor entities
• contracts → Custom fields defined for contract entities
• departments → Custom fields defined for department entities
• request_licenses → Custom fields defined for license request entities
• transactions → Custom fields defined for transaction entities

Each custom field includes:

• field_id → Unique identifier for the field
• field_name → Display name of the field
• field_type → Type of field (text, date, bool, select, reference)
• field_options → Available options (only for select type fields)