Open Graph for Slack
How to configure Open Graph tags for Slack link unfurling, image dimensions, audio/video previews, and workspace security considerations.
Slack is the primary communication tool for thousands of companies. In Slack, when a team member shares a URL, Slack automatically “unfurls” the link to display a preview box with an image, title, and description.
Optimizing Open Graph tags for Slack ensures your internal documentation, blog posts, and product links look professional and informative inside team channels.
Slack Link Unfurling Meta Tags
Slack parses standard Open Graph tags from page headers:
<meta property="og:site_name" content="Company Knowledge Base" />
<meta property="og:title" content="Q3 Product Roadmap & Feature Specs" />
<meta property="og:description" content="Overview of upcoming features, sprint timelines, and architecture plans." />
<meta property="og:image" content="https://example.com/images/roadmap-preview.png" />
<meta property="og:url" content="https://example.com/docs/roadmap" />How Slack Displays Preview Elements
og:site_name: Displayed at the top of the unfurled card next to a favicon.og:title: Displayed as a bold clickable link.og:description: Displayed as clean body text below the title (up to 300 characters).og:image: Rendered below the description as a large inline graphic.
Image Specifications for Slack
- Recommended Dimensions: 1200 × 630 pixels
- Aspect Ratio: 1.91:1
- Max File Size: 5 MB
- Supported Formats: PNG, JPEG, GIF, WebP
If the image is smaller than 200 × 200 pixels, Slack renders it as a tiny square thumbnail on the right side of the text preview rather than a large banner.
Slack Authentication & Internal Links
A common issue in Slack occurs with internal/private URLs (e.g., links behind VPNs or authentication walls):
- If a page requires login authentication, Slack’s crawler (
Slackbot) will receive a 401/403 status or redirect to a login screen. - Solution: Ensure public metadata is accessible to crawlers on login landing pages, or use Slack App Unfurl APIs for private enterprise tools.
Related Resources
- Open Graph for Discord
- Open Graph Tags: Complete List With Examples
- Open Graph Troubleshooting Guide
- Audit your Slack tags with our Open Graph Inspector