diff --git a/pysmsboxnet/api.py b/pysmsboxnet/api.py
index df4604a..dd64b17 100644
--- a/pysmsboxnet/api.py
+++ b/pysmsboxnet/api.py
@@ -12,7 +12,9 @@
 class Client:
     """API client class."""
 
-    def __init__(self, session: ClientSession, host: str, cleApi: str, timeout=30):
+    def __init__(
+        self, session: ClientSession, host: str, cleApi: str, timeout: int = 30
+    ):
         """Initialize the SMS."""
         self.host = host
         self.cleApi = cleApi
diff --git a/pysmsboxnet/exceptions.py b/pysmsboxnet/exceptions.py
index ceac78d..e57f7d5 100644
--- a/pysmsboxnet/exceptions.py
+++ b/pysmsboxnet/exceptions.py
@@ -4,7 +4,7 @@
 class SMSBoxException(BaseException):
     """Base exception for SMSBox API."""
 
-    def __init__(self, message="Unknown API error"):
+    def __init__(self, message: str = "Unknown API error"):
         """Initialize SMSBox base exception.
 
         An optional message can be specified.
@@ -58,6 +58,6 @@ def __init__(self):
 class HTTPException(SMSBoxException):
     """Exception when API returns ERROR 03."""
 
-    def __init__(self, errorCode):
+    def __init__(self, errorCode: int):
         """Initialize HTTP error Exception."""
         super().__init__(f"HTTP error ({errorCode})")