# Facebook link preview checker

> Facebook builds link cards from Open Graph tags fetched by facebookexternalhit. The same cache is shared by Messenger and Instagram DMs.

Check a URL: https://sharelint.pages.dev/?url=<your-url>, or as Markdown: https://sharelint.pages.dev/api/preview?format=md&url=<your-url>

## Tags Facebook reads (fallback order)

- Title: `og:title` -> `<title>`
- Description: `og:description` -> `meta description`
- Image: `og:image` -> `og:image:secure_url`

## Image requirements

- Recommended: 1200×630 (1.91:1)
- Minimum: 200×200
- Maximum weight: 8 MB
- Formats: JPEG, PNG, GIF, WebP

## Card layout

Images at least 600 px wide with a landscape ratio show as a large card. Smaller or square images show as a small thumbnail beside the text.

## Refreshing the cache

Open the Facebook Sharing Debugger, paste the URL and click Scrape Again.

## Common problems

- The image is missing on the first share: add og:image:width and og:image:height so Facebook does not have to download the image first.
- Old title or image: the preview is cached. Scrape it again in the Sharing Debugger.
- Relative og:image paths are ignored. Always use an absolute URL.

Rule confidence: documented.