diff --git a/packages/gatsby/src/commands/serve.ts b/packages/gatsby/src/commands/serve.ts
index 70af66e487492..a13f85b87f1e7 100644
--- a/packages/gatsby/src/commands/serve.ts
+++ b/packages/gatsby/src/commands/serve.ts
@@ -70,7 +70,7 @@ const sanitizeUrl = (url: string): string => {
   try {
     // Decode URL and normalize slashes
     const decoded = decodeURIComponent(url)
-    return decoded.replace(/\/+/g, '/').replace(/\/$/, '') || '/'
+    return decoded.replace(/\/+/g, `/`).replace(/\/$/, ``) || `/`
   } catch (e) {
     report.warn(`Failed to decode URL: ${url}`)
     return url