What Is Open Graph?
Open Graph (OG) is a protocol developed by Facebook that enables web pages to become rich objects in social media. By adding Open Graph meta tags to your page's <head>, you control exactly how your page title, description, and image appear when someone shares your URL on Facebook, LinkedIn, Slack, WhatsApp, and other platforms that support the protocol.
Essential Open Graph tags
og:title, the title shown in the social share card (can differ from your page title). og:description, the summary shown below the title (150 to 200 characters). og:image, the image displayed in the card (minimum 1200×630px recommended for best quality across platforms). og:url, the canonical URL of the page. og:type, the type of content: website for regular pages, article for blog posts. og:site_name, your brand name.
Open Graph image best practices
Use a minimum 1200×630px image (1.91:1 aspect ratio) for best display across platforms. Keep critical content away from edges, some platforms crop images. Use PNG or JPEG; avoid GIFs. Include your logo or brand elements. Create unique OG images per page, a generic image for every page dramatically reduces click-through from social shares.
Why check Open Graph tags
The Open Graph protocol, created by Facebook in 2010, defines <meta property="og:..."> tags that describe a page for social sharing. Almost every platform that builds link previews now reads them, and X also reads its own twitter:card tags. The problem is that these tags are invisible on the page itself, so a broken image path or a description copied from another page goes unnoticed until someone shares the link and gets a blank or wrong card. An Open Graph checker makes the tags visible. The platforms offer their own versions, such as Facebook's Sharing Debugger and LinkedIn's Post Inspector, and independent checkers show several platform previews side by side. Some tools fetch a live URL; others let you type values in and generate the tags, which is useful before a page is published.
How an Open Graph checker works
A URL-based checker behaves like a platform's crawler. It requests the page from a server (Facebook's crawler identifies itself as facebookexternalhit), follows redirects, and parses the <head> of the HTML it receives. It then extracts the Open Graph properties, og:title, og:description, og:image, og:url, og:type and og:site_name, plus optional ones such as og:image:alt, og:image:width and og:image:height, along with twitter:card, twitter:title and twitter:image. From those values it renders mock previews and runs checks. Typical checks are: is each required tag present and non-empty; is og:image an absolute https:// URL that returns an image rather than an error; is the image large enough and close to the 1.91:1 ratio most platforms use for large cards (1200 by 630 pixels is the common recommendation); do the title and description fit before truncation; and does og:url match the canonical URL. Because most of these crawlers do not run JavaScript, tags added only by client-side scripts often appear missing in the checker, which mirrors what the platforms see. Platform debuggers also expose their caches: Facebook's Sharing Debugger has a "Scrape Again" button and LinkedIn's Post Inspector refetches the page, which is how you update a preview that was cached before you fixed the tags.
Testing Open Graph tags
Facebook's Sharing Debugger (developers.facebook.com/tools/debug) lets you preview and refresh OG tags for any URL. LinkedIn Post Inspector (linkedin.com/post-inspector) does the same for LinkedIn. Twitter Card Validator (developer.twitter.com/en/docs/twitter-for-websites/cards/guides/troubleshooting-cards) is equivalent for Twitter. Canvas Builder's /tools/og-preview tool lets you preview OG cards without visiting external tools.
Open Graph checking best practices
Check every important template, not just the homepage: blog posts, product pages and landing pages often inherit wrong or missing tags from a shared layout. Run the checker before launch and again after any change to the page's head, CMS plugins or image paths. Make each page's og:title and og:description specific to that page rather than repeating the site name and tagline everywhere. Use a dedicated share image of 1200 by 630 pixels, keep important text away from the edges so it survives cropping into square previews, and keep the file size modest so crawlers fetch it reliably. Always use absolute HTTPS URLs for og:image and og:url, and add og:image:alt to describe the image. If a platform keeps showing an old preview after you have fixed the tags, force a refresh with the platform's own tool (Facebook's "Scrape Again" or LinkedIn's Post Inspector) rather than waiting for the cache to expire. Test the platforms where your audience actually shares links, because each one crops and truncates differently. Finally, make sure the page returns a 200 status to crawlers and is not hidden behind a login wall, a robots.txt block or aggressive bot protection, any of which can make both the checker and the platforms see an empty page.
Open Graph and Canvas Builder
Canvas Builder generates SEO meta for each page, and after you publish or export a site it is worth confirming the social tags on every key page with a checker before you promote it. canvasbuilder.co offers two free tools for this: the Open Graph Checker builds and previews tags from values you type in, and OG Preview fetches any public HTTPS URL and shows its share card on Facebook, X, LinkedIn and Slack.
Start building freeFrequently asked questions
Are Open Graph tags required for SEO?
OG tags don't directly affect search rankings, but they influence social sharing click-through rates, which can drive traffic. For content marketing, correct OG tags are essential.
Can I use my page title as the OG title?
Yes, and often it's the best choice. However, OG titles can be slightly longer and more 'shareable' in tone. Your page title optimises for Google; your OG title can optimise for social sharing.
How do I check the Open Graph tags on a URL?
Paste the URL into an Open Graph checker such as Facebook's Sharing Debugger, LinkedIn's Post Inspector or an independent preview tool. It fetches the page, lists every og: and twitter: tag it finds and shows how the share card will look. You can also view the page source and search for og: to see the raw tags.
Why is the wrong image showing when I share my link?
Usually the og:image tag is missing or points to a relative or broken URL, or the platform is showing a preview it cached before you fixed the tag. Check the tag with an Open Graph checker, confirm the image URL opens in a browser, then use the platform's debugger to refetch the page.
What size should an Open Graph image be?
1200 by 630 pixels, a 1.91:1 ratio, is the widely recommended size and displays well on Facebook, LinkedIn and most other platforms. Keep key text and logos near the centre, because some apps crop previews to a square. Use JPEG or PNG and keep the file reasonably small.