For Slack unfurls
Check how your URL unfurls inside Slack messages and channels.
Slack reads Open Graph and Twitter Card tags to render its inline preview. Apps with Slack integrations can also use Block Kit unfurls.
The preview unfurls once per workspace per URL and is cached for ~30 minutes before Slack re-fetches.
Slack's fetcher identifies itself as Slackbot and, like every social scraper, reads server-rendered HTML without executing JavaScript. If your og:tags arrive via client-side rendering, Slack falls back to the bare <title> tag or shows nothing. The other classic silent failure: your site's bot protection or firewall blocks Slackbot's requests, and links that preview fine elsewhere show nothing in Slack.
Slack is unusual among preview surfaces in how much internal, authenticated content gets shared there — staging URLs, admin dashboards, docs behind SSO. Slackbot can't log in, so those links unfurl with either nothing or (worse) your login page's generic tags. That's expected behavior, not a bug; for internal tools, a sensible <title> on the login page is the realistic fix.
The ~30-minute cache makes Slack far more forgiving than LinkedIn or Facebook: fix your tags, wait a few minutes, share again in a different message, and the corrected card appears. This makes Slack a decent quick-feedback loop while iterating on OG tags — though this tool is faster still, showing the current tag state without posting anything anywhere.
Unfurl etiquette is a real consideration in shared workspaces: multiple links in one message can produce a wall of preview cards. Slack suppresses unfurls when a URL is wrapped in angle brackets, and workspace admins can disable unfurls per-domain — so if your carefully crafted preview isn't appearing for teammates, check whether the workspace has muted your domain before debugging your tags.
For product teams, remember the distinction between passive unfurls (Slack reading your OG tags — what this tool previews) and app unfurls (your Slack app registering for your domain and rendering rich Block Kit cards). If you need interactive, authenticated, or data-rich previews for your own product's links, that's the app-unfurl path; OG tags are the floor every link should clear regardless.
Make sure docs and announcements unfurl cleanly when shared in #general — the preview is the first impression most of the company gets.
Verify shared resources look polished when shared with customers in Slack Connect channels, where a broken card reads as sloppiness.
Confirm previews look right before dropping launch links into customer channels and communities.
Engineering teams paste docs links into Slack constantly — per-page titles and descriptions turn every paste into a readable card instead of a bare URL.
Links posted by your CI, alerting, or internal bots unfurl with the same OG rules — check the pages your automation links to most.
Pre-configured variants tuned to specific platforms and use cases.
For LinkedIn shares
See how your URL looks when shared on LinkedIn — before you post.
Open variantFor X / Twitter Cards
Preview how your URL renders as a Twitter Card on X.
Open variantFor Facebook shares
Inspect how your URL will render in a Facebook post or share.
Open variantFor Discord embeds
See how Discord embeds your URL inside a channel or DM.
Open variant