Social previews

Glyphfield serves deterministic 1200 × 630 PNG previews from /api/og-home, /api/og, the Next.js file-based OpenGraph routes, and the documentation image route.

Crawler access

public/robots.txt explicitly allows the preview routes for Twitterbot and the common Facebook, LinkedIn, Discord, Slack, Telegram, and Pinterest link-preview crawlers. Keep the following Twitter block when changing the crawler policy:

User-Agent: Twitterbot
Allow: /
Allow: /api/og
Allow: /api/og-home
Allow: /opengraph-image
Allow: /twitter-image

An Allow rule does not create an image endpoint. The route must return a successful image/png response without authentication, cookies, JavaScript, or browser-only state.

Verification

Before deploying, check all three layers:

1. Fetch /robots.txt with the crawler user agent and confirm the image path is allowed.
2. Inspect the page HTML for absolute og:image and twitter:image values.
3. Fetch that exact image URL and confirm a 200 response with content-type: image/png.

Social networks cache previews independently. A correct redeploy may still require the network's card debugger or a versioned image URL before the old card disappears.

Dynamic preview endpoint

GET /api/og accepts bounded title, description, kicker, index, and six-digit accent query parameters. It uses the same renderer and embedded Switzer font files as the homepage, Studio, Twitter, and documentation previews.