diff --git a/site/src/middleware.ts b/site/src/middleware.ts
index 9b570ff2..ce4a0924 100644
--- a/site/src/middleware.ts
+++ b/site/src/middleware.ts
@@ -9,6 +9,8 @@ import GithubSlugger from "github-slugger";
  */
 const addHeadingIds: MiddlewareHandler = async (_, next) => {
   const response = await next();
+  if (response.headers.get("Content-Type") !== "text/html") return response;
+
   const $ = load(await response.text());
   const slugger = new GithubSlugger();
 
diff --git a/site/src/pages/museum/api/search.ts b/site/src/pages/museum/api/search.ts
index 4813013d..e49eac68 100644
--- a/site/src/pages/museum/api/search.ts
+++ b/site/src/pages/museum/api/search.ts
@@ -30,5 +30,7 @@ export const GET: APIRoute = async () => {
       });
   }
 
-  return new Response(JSON.stringify(pageResults));
+  return new Response(JSON.stringify(pageResults), {
+    headers: { "Content-Type": "application/json" },
+  });
 };