diff --git a/.gitignore b/.gitignore
index 93186f9..532c7fb 100644
--- a/.gitignore
+++ b/.gitignore
@@ -5,3 +5,4 @@ __pycache__/
 .devcontainer/
 
 src/.pdm-python
+src/htmlcov
\ No newline at end of file
diff --git a/src/app.py b/src/app.py
index 155c93e..2f04ffc 100644
--- a/src/app.py
+++ b/src/app.py
@@ -45,30 +45,43 @@ global_data = {'username': 'no_user'}
 # incrementation route
 @app.route('/inc')
 def plus_one():
-    x = int(request.args.get('x', 1))
+    try:
+        x = int(request.args.get('x', 1))
+    except:
+        return json.dumps({"error": "Type error"})
+
     return json.dumps({'x': operators.addition(x, 1)})
 
 # addition route, the parameters will be passed with 'x' and 'y'
 @app.route('/add')
 def plus_y():
-    x = int(request.args.get('x', 1))
-    y = int(request.args.get('y', 1))
+    try:
+        x = int(request.args.get('x', 1))
+        y = int(request.args.get('y', 1))
+    except:
+        return json.dumps({"error": "Type error"})
     return json.dumps({'result': operators.addition(x, y)})
 
 
 # multiplication route, the parameters will be passed with 'x' and 'y'
 @app.route('/mul')
 def multiply_y():
-    x = int(request.args.get('x', 1))
-    y = int(request.args.get('y', 1))
+    try:
+        x = int(request.args.get('x', 1))
+        y = int(request.args.get('y', 1))
+    except:
+        return json.dumps({"error": "Type error"})
     return json.dumps({'result': operators.multiplication(x, y)})
 
 
 # division route, the parameters will be passed with 'x' and 'y'
 @app.route('/div')
 def division_y():
-    x = int(request.args.get('x', 1))
-    y = int(request.args.get('y', 1))
+    try:
+        x = int(request.args.get('x', 1))
+        y = int(request.args.get('y', 1))
+    except:
+        return json.dumps({"error": "Type error"})
     return json.dumps({'result': operators.division(x, y)})
 
 
diff --git a/src/tests/test_api.py b/src/tests/test_api.py
index e172bc7..cceefb7 100644
--- a/src/tests/test_api.py
+++ b/src/tests/test_api.py
@@ -17,6 +17,7 @@
 
 from urllib.parse import urlencode
 import json
+import pytest
 
 __author__ = 'Michael Mader'
 __date__ = "2023-03-12"
@@ -63,3 +64,26 @@ def test_multiply(client):
 def test_division(client):
     result = call(client, '/div', {'x': 35, 'y': 7})
     assert result['result'] == 5
+
+# type tests
+def test_type_inc(client):
+    result = call(client, '/inc', {'x': 'a'})
+    assert result["error"] == "Type error"
+
+def test_type_add(client):
+    result = call(client, '/add', {'x': 'a', 'y': 1})
+    assert result["error"] == "Type error"
+    result = call(client, '/add', {'x': 1, 'y': 'a'})
+    assert result["error"] == "Type error"
+
+def test_type_mul(client):
+    result = call(client, '/mul', {'x': 'a', 'y': 1})
+    assert result["error"] == "Type error"
+    result = call(client, '/mul', {'x': 1, 'y': 'a'})
+    assert result["error"] == "Type error"
+
+def test_type_div(client):
+    result = call(client, '/div', {'x': 'a', 'y': 1})
+    assert result["error"] == "Type error"
+    result = call(client, '/div', {'x': 1, 'y': 'a'})
+    assert result["error"] == "Type error"
\ No newline at end of file