OG Tag Previewer — Check Your Social Link Preview

Open Graph (OG) tags are HTML meta tags that control how a page appears when someone shares its URL on Facebook, LinkedIn, Slack, iMessage, WhatsApp, or any platform that supports link unfurling. When you paste a URL into Facebook, Facebook's crawler reads the og:title, og:description, and og:image tags from the page's HTML and uses them to build the preview card. Without these tags, platforms fall back to the HTML title and page description — often producing a card that looks nothing like intended.

Required vs. optional Open Graph tags

Three tags are required for a well-formed link preview: og:title (the card headline), og:description (the card subtext), and og:image (the card thumbnail). Two tags are strongly recommended: og:type (typically "website" or "article") and og:url (the canonical URL of the page, which prevents duplicate cards when the URL is shared with tracking parameters). Twitter/X also requires a twitter:card meta tag to activate its card rendering; without it, Twitter defaults to a plain text link with no image, regardless of the og:image present.

Why your og:image might not show

The most common failure mode is an og:image that is technically present but inaccessible or undersized. Platforms require the image URL to return HTTP 200 with no authentication, and the image must be at least 200×200 pixels — most platforms recommend 1200×630 pixels for optimal rendering. A second common issue is Facebook's image CDN cache: once Facebook has crawled a URL, it caches the og:image for up to 30 days. Even after you update the image on your server, Facebook continues showing the old one until the cache expires or you submit the URL to the Facebook Sharing Debugger to force a rescrape. Running this tool before publishing catches both problems — inaccessible images and missing tags — before they affect real shares.

og:title vs HTML title

When og:title is absent, Facebook, LinkedIn, and most platforms fall back to the page's HTML <title> element. The problem: HTML titles are typically formatted as "Product Name — Site Name" or "Article Headline | Brand | Year" to satisfy browser tab and search result conventions. In a social card, the site name suffix wastes headline space and looks unprofessional. og:title lets you set a separate, optimized card headline that works as a social share teaser — shorter, punchier, with no site name appended.

Twitter/X cards

Twitter/X uses its own card system, but reads og:title, og:description, and og:image as fallbacks when the twitter:* equivalents are absent. The twitter:card tag opts the page into one of four card formats: summary (small thumbnail, left-aligned), summary_large_image (full-width image above the text — the most common format for content pages), app (for mobile app deep links), and player (for video/audio players). Without twitter:card, Twitter renders only a plain link with no preview image, even if og:image is correctly set.