diff --git a/api/robots.txt.ts b/api/robots.txt.ts
index b8115f8..e65d14c 100644
--- a/api/robots.txt.ts
+++ b/api/robots.txt.ts
@@ -10,6 +10,7 @@ export default async (
     return res.status(405).send({ error: 'method not allowed' })
   }
 
+  // cache robots.txt for up to 60 seconds
   res.setHeader(
     'Cache-Control',
     'public, s-maxage=60, max-age=60, stale-while-revalidate=60'
diff --git a/api/sitemap.xml.ts b/api/sitemap.xml.ts
index 29b942a..f591ed8 100644
--- a/api/sitemap.xml.ts
+++ b/api/sitemap.xml.ts
@@ -14,6 +14,7 @@ export default async (
 
   const siteMaps = await getSiteMaps()
 
+  // cache sitemap for up to one hour
   res.setHeader(
     'Cache-Control',
     'public, s-maxage=3600, max-age=3600, stale-while-revalidate=3600'