diff --git a/src/youtube_handler.py b/src/youtube_handler.py
index 7d91194..2a12d82 100644
--- a/src/youtube_handler.py
+++ b/src/youtube_handler.py
@@ -59,6 +59,8 @@ def init_youtube():
 
 
 def is_youtube_url(url: str) -> bool:
+    if not isinstance(url, str):
+        return False
     return "youtube.com" in url or "youtu.be" in url
 
 
diff --git a/tests/test_is_youtube_url_nonstring.py b/tests/test_is_youtube_url_nonstring.py
new file mode 100644
index 0000000..1a9254f
--- /dev/null
+++ b/tests/test_is_youtube_url_nonstring.py
@@ -0,0 +1,14 @@
+from src.youtube_handler import is_youtube_url
+
+
+def test_is_youtube_url_handles_non_string():
+    # `"youtube.com" in url` raises TypeError on a non-string; a url field that
+    # can be None/other (e.g. from a JSON message) should just be "not YT".
+    assert is_youtube_url(123) is False
+    assert is_youtube_url(None) is False
+    assert is_youtube_url({"u": 1}) is False
+
+
+def test_is_youtube_url_detects_real_urls():
+    assert is_youtube_url("https://www.youtube.com/watch?v=x") is True
+    assert is_youtube_url("https://youtu.be/x") is True