Caching

OpenGraph+ reads HTTP cache headers from your pages to decide when to re-render social card images. Since Astro can run in both static and SSR modes, how you configure caching depends on your setup.

This page covers the Astro side. For how OpenGraph+ handles caching at the HTTP level, see the HTTP Caching guide.

Static mode (default)

Astro generates static HTML by default. Cache headers come from your hosting provider, not Astro itself.

Netlify / Cloudflare Pages

Create a _headers file in your public/ directory:

# public/_headers
/*
  Cache-Control: public, max-age=604800

Vercel

Add headers to your vercel.json:

{
  "headers": [
    {
      "source": "/(.*)",
      "headers": [
        { "key": "Cache-Control", "value": "public, max-age=604800" }
      ]
    }
  ]
}

SSR mode

With output: 'server' or output: 'hybrid', you can set cache headers directly in your pages:

---
Astro.response.headers.set('Cache-Control', 'public, max-age=86400')
---
<html>
  <head>...</head>
  <body>...</body>
</html>

This gives you per-page control over caching.

Meta tag overrides

If you can’t control HTTP headers (or want per-page control in static mode), use meta tags directly in your HTML:

<meta property="og:plus:cache:max_age" content="86400">
<meta property="og:plus:cache:etag" content="v1.2.3">

When the etag changes, OpenGraph+ re-renders even if the cache hasn’t expired. These meta tags take priority over HTTP headers.

See the HTTP Caching guide for the full reference on cache headers and meta tag overrides.

Purging

Force an immediate re-render from the OpenGraph+ dashboard by purging the cached image for any URL.

Recommendations

Page type	Strategy
Static pages	Long TTL via hosting headers (7 days)
Blog posts	Medium TTL (1 day) + etag meta tag
Dynamic SSR pages	`Cache-Control` header per-page (1-24 hours)
Frequently updated	Short TTL + etag for instant invalidation