Which tags does Slack use for link previews?

Slack reads Open Graph tags and also some twitter: tags. og:title, og:description, og:image, and og:site_name are the main ones.

Why does Slack show an old preview?

Slack caches unfurls. A link that has already been shared may keep its old card for a while, so test changes with a new URL or after the cache expires.

Does Slack need a specific image size?

No strict size. A standard 1200 × 630 px image works well because Slack scales it to fit.

Will Google display this exact title and description?

Not necessarily. Search engines can rewrite snippets based on the query and page content. The preview helps you plan clear metadata but cannot guarantee the final search result.

Should the canonical URL be absolute?

Yes. Use the preferred public HTTPS URL for the page, including the correct hostname and path.

Does this tool download or validate my social image?

PostlyBee does not download or validate the image. Your browser loads it from its address so the preview can show it. Validate the deployed image dimensions, format, and availability separately.

Are special characters escaped in the copied HTML?

Yes. The generated title and meta values escape HTML-sensitive characters before they are copied.

Does PostlyBee crawl the URL I enter?

Only when you choose Fetch tags. PostlyBee then downloads that one public HTTPS page to read its title, description, and image tags, and does not store it. Private, local, and internal addresses are blocked. Text you type by hand never leaves your browser.

Slack Link Unfurl Preview

Preview how Slack expands a pasted link, then copy the tags that control it. Runs in your browser.

No account needed. Import a live URL or type it in
Slack preview updates instantly
Copy escaped HTML metadata in one action

Page metadata

Page title47 characters · recommended 30–60 · Good lengthMeta description93 characters · recommended 60–160 · Good lengthCanonical URLSite nameSocial image URL

Slack reads: og:title, og:description, og:image, og:site_name, twitter:card

Slack

PostlyBee

Plan and schedule social content with PostlyBee

Create, customize, preview, and schedule social media posts from one collaborative workspace.

Image: 1200 × 630 px. Slack scales the image to fit the unfurl, so a standard 1.91:1 image works well.

Generated HTML

<meta property="og:title" content="Plan and schedule social content with PostlyBee" />
<meta property="og:description" content="Create, customize, preview, and schedule social media posts from one collaborative workspace." />
<meta property="og:image" content="https://postlybee.com/og-image.png" />
<meta property="og:site_name" content="PostlyBee" />
<meta name="twitter:card" content="summary_large_image" />

From link to published

Check it here, publish to Slack with PostlyBee

The same editor you use for every post, in a few steps.

Enter any public page URL and PostlyBee reads its title, description, and image for you, so there is nothing to retype.

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Import from a live page

Fetch tags

Title

Description

Image

Practical guide

Make links useful in team chat

A link pasted into Slack is judged in seconds, usually by people who know nothing about the page. A clear title and a one-line description tell them whether to open it.

Slack keeps unfurls cached, so changes can take a while to appear on a link that was already shared. Test with a fresh URL when you are iterating.

Privacy: Text you type stays in this browser tab. If you import a URL, PostlyBee downloads that public page once to read its tags and does not store it. Your browser loads the preview image directly from its address.

01
Name the site
Set og:site_name so the unfurl shows your brand.
02
Write title and description
Make both understandable without clicking the link.
03
Copy and test
Paste the tags into the page and drop the live URL into a Slack message.

Pro tips

Pro tips for Slack metadata

Site name leads the unfurl

Slack shows the site name above the title. Set og:site_name so it reads as your brand and not a bare domain.

Open Graph and card tags are read

Slack uses og: tags and also reads twitter: tags. A complete og: set is usually enough.

Long text is trimmed

Long descriptions are cut and may expand behind a "Show more" control. Put the useful part first.

FAQ

About the Slack Meta Tags Preview

Know what the preview measures, what it does not guarantee, and how your input is handled.

Ready to move from preview to publishing?

Use this free tool without an account, then bring the finished work into PostlyBee to customize, schedule, and track the campaign.

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