diff --git a/zerver/webhooks/sentry/doc.md b/zerver/webhooks/sentry/doc.md
index 374163d298..55303d84c0 100644
--- a/zerver/webhooks/sentry/doc.md
+++ b/zerver/webhooks/sentry/doc.md
@@ -1,5 +1,9 @@
 Get Zulip notifications for the issues in your Sentry projects!
 
+This integration supports Sentry's Node, Python, and Go
+[platforms](https://sentry.io/platforms/).  [Contact
+us](/help/contact-support) if a platform you care about is missing.
+
 1. {!create-stream.md!}
 
 2. {!create-bot-construct-url-indented.md!}
diff --git a/zerver/webhooks/sentry/view.py b/zerver/webhooks/sentry/view.py
index 85facd90e6..7b4f91d6f0 100644
--- a/zerver/webhooks/sentry/view.py
+++ b/zerver/webhooks/sentry/view.py
@@ -66,7 +66,6 @@ Issue **{title}** was ignored by **{actor}**.
 platforms_map = {
     "go": "go",
     "node": "javascript",
-    "javascript": "javascript",
     "python": "python3",
 }  # We can expand this as and when users use this integration with different platforms.
 
@@ -102,7 +101,10 @@ def handle_event_payload(event: Dict[str, Any]) -> Tuple[str, str]:
         # (in the Python Sentry SDK) or something similar.
 
         filename = event["metadata"]["filename"]
-        platform = platforms_map[event["platform"]]
+        platform_name = event["platform"]
+        platform = platforms_map.get(platform_name)
+        if platform is None:  # nocoverage
+            raise UnexpectedWebhookEventType("Sentry", f"platform {platform_name}")
 
         stacktrace = None
         for value in event["exception"]["values"]: