# FormItemServerValidationType (Complex Type)

### Namespace: http://midpoint.evolveum.com/xml/ns/public/common/common-3

Server-side validation rules.

Item Summary
Name | Type | Multiplicity | Description
--- | --- | --- | ---
expression | property ExpressionType | [0,1] | Validation expression.

- ### Items

  - #### expression

    Flags: RAM,runtime

    Multiplicity: [0,1]

    Display order:

    Validation expression. Value of the validated input will be passed as expression variable. The expression is supposed to return operation result (OperationResult) indicating success, failure and providing an optional message. Null output is considered to be validation success.