Launchpack by Świt StudioSlack link preview: what Slack shows, and how to fix a missing unfurl
Slack calls link previews unfurls. It reads the same Open Graph tags as other apps but shows them differently, with the image smaller than on X or LinkedIn.
Slack shows your site name (og:site_name) and favicon, the title as a link, the description, then the og:image scaled down to a compact width.
Use the usual 1200 × 630 image with large, short text, and make sure the page is publicly reachable: Slack fetches it from its own servers.
What Slack shows
| Part of the unfurl | Comes from |
|---|---|
| Site name and small icon | og:site_name and your favicon |
| Linked title | og:title (or <title>) |
| Description | og:description |
| Image | og:image, shown at a compact width |
Add og:site_name: without it the top line falls back to the domain. A missing favicon leaves an empty spot next to it; the favicon checker shows whether yours loads.
Designing for a small image
- Big headline, few words: the image is often under 400 px wide in Slack.
- Brand color background, so it's recognisable at a glance.
- No fine print or URLs on the image; the title and description are right above it.
When a link doesn't unfurl
- The page needs a login, sits behind a VPN, or blocks bots: Slack's crawler can't read it.
- The tags are added by JavaScript: crawlers don't run it.
- The workspace or the sender turned off previews for that domain or message. A removed preview stays removed for that message.
- Old cache: post the link with a new query string (
?v=2).
The full list of causes is in OG image not showing, and the link preview checker shows a Slack-style preview of your page.
An image that reads small
Launchpack's layouts keep the headline big at every size.
Questions
Why doesn't my link unfurl in Slack?
Slack's crawler couldn't read the page (login, VPN, bot protection), the tags are added by JavaScript, previews were turned off for that link, or an old result is cached. Post it again with ?v=2 after fixing.
Why is the image small in Slack?
Slack shows og:image at a compact width under the text. Use large, short text on the image so it still reads.
What does og:site_name do in Slack?
It's the line above the title, next to your favicon. Without it Slack shows the domain.