diff --git a/api/top-langs.js b/api/top-langs.js
index cde0a9a..f01648e 100644
--- a/api/top-langs.js
+++ b/api/top-langs.js
@@ -44,6 +44,16 @@ export default async (req, res) => {
     return res.send(renderError("Something went wrong", "Locale not found"));
   }
 
+  if (
+    layout !== undefined &&
+    (typeof layout !== "string" ||
+      !["compact", "normal", "donut", "donut-vertical", "pie"].includes(layout))
+  ) {
+    return res.send(
+      renderError("Something went wrong", "Incorrect layout input"),
+    );
+  }
+
   try {
     const topLangs = await fetchTopLanguages(
       username,
diff --git a/src/cards/top-languages-card.js b/src/cards/top-languages-card.js
index 92f5b9d..23c76bc 100644
--- a/src/cards/top-languages-card.js
+++ b/src/cards/top-languages-card.js
@@ -746,7 +746,7 @@ const renderTopLanguages = (topLangs, options = {}) => {
       totalLanguageSize,
       hide_progress,
     );
-  } else if (layout?.toLowerCase() === "donut") {
+  } else if (layout === "donut") {
     height = calculateDonutLayoutHeight(langs.length);
     width = width + 50; // padding
     finalLayout = renderDonutLayout(langs, width, totalLanguageSize);