The following are the validators you can add to your issues' workflows out of the box. Learn more about using validators with custom fields.
Default workflow validators
Date Compare Validator
Compare two dates during a workflow transition.
Date Window Validator
Compares two date fields, by adding a time span in days to one of them.
Field Required Validator
Field must not be empty during the transition.
Field has been modified Validator
Field value must be changed during the transition.
Field has single value Validator
Multi-select Field has not more than one value during transition.
Parent Status Validator
Validates that the parent issue is in required state.
Validates that the user has a permission.
Previous State Validator
Validates that the issue has previously transitioned through a specific state.
Regular Expression Check
Validate field contents against a regular expression during a workflow transition.