Jetstack's string-family filters support:
nullnot_nullisis_notcontainsnot_containsin_listnot_in_listnull and not_nullUse these when you only care whether a value exists.
is and is_notUse these for direct string equality or inequality checks.
contains and not_containsUse these when partial match semantics are intended. The platform automatically expands the search string into a wildcard pattern if needed.
in_list and not_in_listUse these when the candidate set should come from a managed filter list instead of being repeated inside many query definitions.
For title-like enumeration values, the platform may resolve translated values before comparing. This is important in multilingual implementations because a filter may operate on the translated display value rather than only on the stored base value.
This family is the right fit when the stored meaning is primarily textual and you need:
Use in_list for approved categories maintained by operators in a filter list instead of embedding the allowed values into several query definitions.
contains only when partial match semantics are really intended