Reference

Open Graph glossary

Every og tag and link-preview term, defined in one plain-English sentence each.

Open Graph protocol

A metadata standard created by Facebook in 2010. A page declares og: meta tags so any platform can build a rich link card from them.

og:title

The headline shown on the link card. Keep it under 60 characters; it can differ from the HTML <title>.

og:description

The supporting line under the headline. Shown by Facebook, Slack, WhatsApp and Discord — never by LinkedIn.

og:image

The card image, as an absolute https URL. Export at 1200x630 PNG or JPEG, under 300 KB for WhatsApp.

og:image:width / og:image:height

Declared pixel dimensions so a platform can lay out the card on first share before it downloads the image.

og:image:alt

Alt text for the card image, read by screen readers.

og:url

The canonical address of the page, so tracked or mirrored URLs all resolve to one card and one cache entry.

og:type

The content kind — website for most pages, article for posts.

og:site_name

Your brand name, shown above the headline in Slack and Discord.

Twitter Card

X's parallel metadata set using twitter: names. X falls back to og: tags except for twitter:card.

twitter:card

The X layout switch. summary_large_image gives the full-width image; summary gives a small square.

Scraping

When a platform's crawler fetches your URL to read its tags and build the card.

Cache

Platforms store the first card they built. LinkedIn holds it about a week; Facebook needs a manual re-scrape in its Sharing Debugger.

Canonical URL

The single official address of a page, declared with a canonical link tag or og:url, so duplicates do not compete.

Unfurling

Slack's term for expanding a pasted link into a card.

1.91:1

The aspect ratio shared by the large cards on Facebook, LinkedIn and X — 1200x630 pixels.