# Validation

- [HasValue](/platform/wemreference/functions/validation/hasvalue.md)
- [IsEmpty](/platform/wemreference/functions/validation/isempty.md)
- [IsKnown](/platform/wemreference/functions/validation/isknown.md)
- [IsUnknown](/platform/wemreference/functions/validation/isunknown.md)
- [IsValidBankaccount](/platform/wemreference/functions/validation/isvalidbankaccount.md)
- [IsValidBSN](/platform/wemreference/functions/validation/isvalidbsn.md)
- [IsValidBTW](/platform/wemreference/functions/validation/isvalidbtw.md)
- [IsValidEmailAddress](/platform/wemreference/functions/validation/isvalidemailaddress.md)
- [IsValidIBAN](/platform/wemreference/functions/validation/isvalidiban.md)
- [IsValidPhonenumber](/platform/wemreference/functions/validation/isvalidphonenumber.md)
- [IsValidURL](/platform/wemreference/functions/validation/isvalidurl.md)