diff --git a/src/corelibs/check_handling/regex_constants.py b/src/corelibs/check_handling/regex_constants.py
index f71603e..aa7fba9 100644
--- a/src/corelibs/check_handling/regex_constants.py
+++ b/src/corelibs/check_handling/regex_constants.py
@@ -19,19 +19,19 @@ def compile_re(reg: str) -> re.Pattern[str]:
 
 
 # email regex
-EMAIL_BASIC_REGEX = r"""
+EMAIL_BASIC_REGEX: str = r"""
 ^[A-Za-z0-9!#$%&'*+\-\/=?^_`{|}~][A-Za-z0-9!#$%:\(\)&'*+\-\/=?^_`{|}~\.]{0,63}
 @(?!-)[A-Za-z0-9-]{1,63}(?<!-)(?:\.[A-Za-z0-9-]{1,63}(?<!-))*\.[a-zA-Z]{2,6}$
 """
 # Domain regex with localhost
-DOMAIN_WITH_LOCALHOST_REGEX = r"""
+DOMAIN_WITH_LOCALHOST_REGEX: str = r"""
 ^(?:localhost|(?!-)[A-Za-z0-9-]{1,63}(?<!-)(?:\.[A-Za-z0-9-]{1,63}(?<!-))*\.[A-Za-z]{2,})$
 """
 # domain regex with loclhost and optional port
-DOMAIN_WITH_LOCALHOST_PORT_REGEX = r"""
+DOMAIN_WITH_LOCALHOST_PORT_REGEX: str = r"""
 ^(?:localhost|(?!-)[A-Za-z0-9-]{1,63}(?<!-)(?:\.[A-Za-z0-9-]{1,63}(?<!-))*\.[A-Za-z]{2,})(?::\d+)?$
 """
 # Domain, no localhost
-DOMAIN_REGEX = r"^(?!-)[A-Za-z0-9-]{1,63}(?<!-)(?:\.[A-Za-z0-9-]{1,63}(?<!-))*\.[A-Za-z]{2,}$"
+DOMAIN_REGEX: str = r"^(?!-)[A-Za-z0-9-]{1,63}(?<!-)(?:\.[A-Za-z0-9-]{1,63}(?<!-))*\.[A-Za-z]{2,}$"
 
 # __END__