diff --git a/backend/src/api/controllers/user.ts b/backend/src/api/controllers/user.ts
index 365989eba..e8ee7205c 100644
--- a/backend/src/api/controllers/user.ts
+++ b/backend/src/api/controllers/user.ts
@@ -498,6 +498,16 @@ export async function addTag(
   const { uid } = req.ctx.decodedToken;
   const { tagName } = req.body;
 
+  const user = await UserDAL.getUser(uid, "add tag");
+
+  if (!user) {
+    throw new MonkeyError(404, "User not found");
+  }
+
+  if ((user?.tags?.length ?? 0) >= 10) {
+    throw new MonkeyError(400, "You can only have up to 10 tags");
+  }
+
   const tag = await UserDAL.addTag(uid, tagName);
   return new MonkeyResponse("Tag updated", tag);
 }