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SEO Analyzer · AI Humanizer · App Icons Generator
Slack link unfurl preview

Slack Link Preview Checker

Paste a public URL to preview how Slack will unfurl it: the site name and icon, title, description, image and any extra label fields. The checker reads the same tags Slack does and explains why an unfurl is missing or wrong.

Try: a GitHub repo · a page with no tags 10 checks left today

Preview

An approximation of each app’s layout. Apps change their designs and crop images differently.

What to fix

Refresh a cached preview

These results show your page as it is right now. An app that already saw the link may keep showing its older, cached preview until it fetches the page again:

  • Facebook & Messenger: open Meta’s Sharing Debugger, paste the URL and press Scrape Again.
  • LinkedIn: paste the URL into LinkedIn’s Post Inspector to fetch it again.
  • Telegram: send the URL to @WebpageBot in Telegram to update its stored preview.
  • WhatsApp, Discord, Slack & iMessage: there is no public refresh tool. Share the URL with a harmless query string added, such as ?v=2, so it counts as a new link.
  • X: start a new post with the link to see the current card; existing posts keep the card they were published with.

Tags found

Suggested tags

A complete set based on what we found. Replace any placeholder values, then paste it into the page’s <head>, or into your CMS or SEO plugin’s social settings.


          
        

      


            
    

  






  

    

      

        
How Slack builds a link preview

        
        
Slack calls link previews unfurls. When a link is posted, Slack’s crawler (user agent Slackbot-LinkExpanding) fetches the page and reads oEmbed, Twitter Card and Open Graph tags:

        
    
          
  • og:site_name and the site icon — the bold first line.
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  • og:title — the blue link.
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  • og:description — the text under it.
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  • og:image — a thumbnail on the right, or a larger image under the text for pages that use twitter:card = summary_large_image.
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  • twitter:label1 / twitter:data1 (and label2 / data2) — small extra fields, such as “Reading time: 6 min” or “Price: $49”. Few sites use them, and they make an unfurl stand out.
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Pages that offer oEmbed, such as video players, may unfurl from oEmbed instead. Like other crawlers, Slack reads the raw HTML without running JavaScript.
        

          
See which of these tags your page has, and what Slack will show.

          Check a URL
        

      


      

        
Why your Slack preview is missing or wrong

        

                    
Previews are switched off for your account
Each member can turn off text previews and images from linked websites in Preferences, under Messages & media. If only you are missing the unfurl, look there first.

                    
An admin blocked previews for the domain
Workspace owners and admins can stop link previews for specific domains. Links to a blocked domain post as plain text for everyone in the workspace.

                    
The preview was removed
Whoever posted a message can remove its unfurl. Removed previews do not come back when the message is edited.

                    
Slackbot cannot load the page
Bot protection, a firewall, or a page that needs a login means Slack gets nothing to unfurl. Allow the Slackbot-LinkExpanding user agent if your firewall challenges bots.

                    
The page has no Open Graph tags
Slack then falls back to the page title, or shows no preview. The issue list below names exactly which tags are missing.

                    
The image is not usable
A relative URL, an image that returns an error, an SVG file or a very large file leaves the unfurl without a picture.

                  

      


      

        
How to refresh Slack’s cached preview

        
        
Slack caches the unfurl it built for a URL for a while, so re-posting the same link can show the old version after you fix the page. There is no public tool to clear it.

        
To check a fix, post the URL with a harmless query string such as ?v=2. Slack treats it as a new link and unfurls it again. Unfurls on messages that were already posted stay as they were.
      


      

        
The best share image for Slack

        
        
Use a 1200 × 630 px JPG or PNG. Small or square images are shown as a thumbnail, so make sure the image still reads when it is shrunk. Add a site icon (<link rel="icon"> or an apple-touch-icon) so the unfurl’s first line carries your logo.

        
To add extra fields under the description:


<meta name="twitter:label1" content="Reading time">
<meta name="twitter:data1" content="6 min">
<meta name="twitter:label2" content="Updated">
<meta name="twitter:data2" content="12 November 2026">
      


      

        
Slack preview questions

        

                    

            

              
            

            

              
Slack prefers og:title over the <title> tag. If the two differ, the unfurl uses og:title. Check the "Tags found" table in the results to see both.

            

          

                    

            

              
            

            

              
Add twitter:label1 and twitter:data1 meta tags (and label2/data2 for a second field). Slack shows each pair as a small field under the description.

            

          

                    

            

              
            

            

              
Text and image previews can be switched off per person, in Preferences under Messages & media. An unfurl that others can see but you cannot is almost always this setting.

            

          

                    

            

              
            

            

              
Not from Open Graph tags, because Slack’s crawler cannot log in. Companies that need previews of private pages build a Slack app that uses Slack’s link unfurling API to supply the preview.

            

          

                    

            

              
            

            

              
Slack caches unfurls. If this checker shows the new image, your page is fixed. Post the URL with ?v=2 added to see the new unfurl immediately.

            

          

                  

      


      

        
Check the preview on other apps

        
Every app reads the same Open Graph tags but shows them differently. The checker above previews all of them at once; these pages explain each app’s own rules.

        

          WhatsApp
                    Discord
                    Slack
                    Telegram
                    iMessage
                    LinkedIn
                    Facebook
                    X (Twitter)
                  

        
Seeing the wrong image on every app? Our guide Link Preview Showing the Wrong Image? How to Clear the Cache on Every Platform covers the fixes in one place.

      


      

        
See your Slack preview before you share the link

        
Check the tags, test the image, and fix the preview in minutes. Free, no signup.

        Check a URL