From 98d16686dc4f3993a9d7fa49544af0fa894c6eb0 Mon Sep 17 00:00:00 2001
From: Paul Bakaus <paul.bakaus@gmail.com>
Date: Sun, 8 Mar 2026 17:10:04 -0700
Subject: [PATCH] Add edge cache headers to all API routes to reduce Vercel
 function invocations

All API routes serve static content that only changes at deploy time, but had
0% cache hit rate. Adding s-maxage=86400 lets Vercel's CDN cache responses at
the edge, which should take the ~28K daily API requests from 0% to ~99% cache.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
---
 api/command-source/[id].js             | 1 +
 api/commands.js                        | 1 +
 api/download/[type]/[provider]/[id].js | 1 +
 api/download/bundle/[provider].js      | 1 +
 api/patterns.js                        | 1 +
 api/skills.js                          | 1 +
 6 files changed, 6 insertions(+)

diff --git a/api/command-source/[id].js b/api/command-source/[id].js
index 848afa85d..f6a7a3c73 100644
--- a/api/command-source/[id].js
+++ b/api/command-source/[id].js
@@ -23,6 +23,7 @@ export default function handler(req, res) {
     }
 
     const content = readFileSync(commandPath, "utf-8");
+    res.setHeader("Cache-Control", "public, s-maxage=86400, stale-while-revalidate=3600");
     res.status(200).json({ content });
   } catch (error) {
     console.error("Error in /api/command-source:", error);
diff --git a/api/commands.js b/api/commands.js
index 5c2107be3..e34b38acf 100644
--- a/api/commands.js
+++ b/api/commands.js
@@ -39,6 +39,7 @@ export default function handler(req, res) {
       }
     }
 
+    res.setHeader("Cache-Control", "public, s-maxage=86400, stale-while-revalidate=3600");
     res.status(200).json(commands);
   } catch (error) {
     console.error("Error in /api/commands:", error);
diff --git a/api/download/[type]/[provider]/[id].js b/api/download/[type]/[provider]/[id].js
index 307ffd047..20869e18a 100644
--- a/api/download/[type]/[provider]/[id].js
+++ b/api/download/[type]/[provider]/[id].js
@@ -62,6 +62,7 @@ export default function handler(req, res) {
 
     const content = readFileSync(filePath);
     const fileName = basename(filePath).replace(/[^a-zA-Z0-9._-]/g, '');
+    res.setHeader("Cache-Control", "public, s-maxage=86400, stale-while-revalidate=3600");
     res.setHeader("Content-Type", "application/octet-stream");
     res.setHeader("Content-Disposition", `attachment; filename="${fileName}"`);
     res.send(content);
diff --git a/api/download/bundle/[provider].js b/api/download/bundle/[provider].js
index e10dc739a..39a9c3ba2 100644
--- a/api/download/bundle/[provider].js
+++ b/api/download/bundle/[provider].js
@@ -26,6 +26,7 @@ export default function handler(req, res) {
     }
 
     const content = readFileSync(zipPath);
+    res.setHeader("Cache-Control", "public, s-maxage=86400, stale-while-revalidate=3600");
     res.setHeader("Content-Type", "application/zip");
     const safeProvider = provider.replace(/[^a-zA-Z0-9._-]/g, '');
     res.setHeader("Content-Disposition", `attachment; filename="impeccable-style-${safeProvider}.zip"`);
diff --git a/api/patterns.js b/api/patterns.js
index 52eb0956e..aa7b65075 100644
--- a/api/patterns.js
+++ b/api/patterns.js
@@ -10,6 +10,7 @@ export default function handler(req, res) {
   try {
     // Extract patterns from SKILL.md using the shared utility
     const { patterns, antipatterns } = readPatterns(PROJECT_ROOT);
+    res.setHeader("Cache-Control", "public, s-maxage=86400, stale-while-revalidate=3600");
     res.status(200).json({ patterns, antipatterns });
   } catch (error) {
     console.error("Error in /api/patterns:", error);
diff --git a/api/skills.js b/api/skills.js
index e91ed2541..4e0bca44d 100644
--- a/api/skills.js
+++ b/api/skills.js
@@ -36,6 +36,7 @@ export default function handler(req, res) {
       }
     }
 
+    res.setHeader("Cache-Control", "public, s-maxage=86400, stale-while-revalidate=3600");
     res.status(200).json(skills);
   } catch (error) {
     console.error("Error in /api/skills:", error);