Why your link looks wrong when you share it

You paste a link into Slack or WhatsApp or LinkedIn and what appears is your logo, a fragment of navigation text, and a title that ends mid-word. Nothing is broken. The platform simply had nothing to go on and guessed.

What actually happens when you paste a link

The platform fetches your page with its own bot, looks for a specific set of meta tags, and builds a preview card. If the tags are there it uses them exactly. If they are not, it falls back to heuristics: the <title>, the meta description, and the first image it finds that is big enough — which is very often a logo, an avatar or a decorative background.

The tags come from the Open Graph protocol, originally Facebook's, now honoured by essentially everything: LinkedIn, WhatsApp, Slack, Discord, Signal, iMessage, Telegram, Teams. Support one standard and you have supported all of them.

The four that matter

<meta property="og:title" content="Your headline here">
<meta property="og:description" content="One or two sentences.">
<meta property="og:image" content="https://example.com/preview.jpg">
<meta property="og:url" content="https://example.com/page">

Notes that catch people out:

• property, not name. Open Graph uses RDFa syntax. Writing name="og:title" is a silent no-op and it is a very common mistake.
• The image URL must be absolute. Relative paths fail everywhere. It must also be publicly reachable — no login, no staging password.
• og:url should be the canonical URL. It is what gets shared onward, and it is how platforms consolidate share counts.
• og:type is website for most pages, article for editorial content.

The image

The preview image is most of the reason a link gets clicked, and it has real constraints.

• 1200 × 630 pixels is the standard. That is 1.91:1, which is what nearly every platform crops to.
• Under 1 MB, ideally well under. Some platforms give up on slow images and fall back to no preview at all.
• JPG or PNG. WebP support in social crawlers is still patchy in 2026 — this is one of the last places where WebP is a genuine risk rather than an obvious win.
• Keep text away from the edges. Different platforms crop differently, and some show a square. Anything essential belongs in the middle 80%.
• Legible at thumbnail size. Most people see this at 300 pixels wide in a chat. Small text is decoration, not information.

Twitter Cards

X uses its own tags, but falls back to Open Graph for anything missing. So you only need two extra lines:

<meta name="twitter:card" content="summary_large_image">
<meta name="twitter:site" content="@yourhandle">

Note name here, not property — the two standards genuinely differ on this, which is exactly why people get it wrong in both directions.

summary_large_image is the wide card and is almost always what you want. Plain summary gives a small square thumbnail that occupies far less space in a feed.

The caching problem

This is the part that causes the most frustration. Platforms cache your preview aggressively — often for days, sometimes indefinitely. Fix your tags after a link has been shared and the old, wrong preview keeps appearing, which makes it look as though your fix did not work.

Each platform has its own way of clearing it:

• Facebook and Instagram — the Sharing Debugger, with a "Scrape Again" button
• LinkedIn — the Post Inspector
• X — no manual tool any more; it re-fetches on its own schedule
• WhatsApp, Slack, Discord — no tool at all. Appending a harmless query parameter (?v=2) produces a URL they have not seen and so a fresh fetch, which is the standard workaround.

The lesson is to get the tags right before a page is shared widely, because fixing them afterwards is genuinely awkward.

Checking it

Our Open Graph checker fetches a URL and shows the tags as actually served, plus how the card will look — which is the fast way to catch the name/property mix-up, a relative image path, or an image that returns 404 from outside your network. The generator and Twitter card generator produce the full set for a page.

Test with the real page on the real domain. A local URL is unreachable by every social crawler, so previewing from localhost tells you nothing.

Two mistakes worth avoiding

One image for the whole site. Technically fine, and it means every article you share looks identical in a feed. A per-page image — even a simple auto-generated one with the headline on a branded background — is a large improvement over a logo repeated fifty times.

Different content in the tags than on the page. Writing an og:title that promises something the page does not deliver is clickbait, it is detectable, and platforms increasingly act on it. The tags should be the page's best honest summary, not a different pitch.