Supported Open Graph tags
Signal reads the bare minimum:
| Tag | Purpose |
|---|---|
og:title |
Preview title |
og:description |
Preview description text |
og:image |
Preview image |
That’s it. No og:video, og:audio, og:url, or og:site_name. No inline media playback, no canonical URL resolution, no site name display.
The og:image URL must be absolute HTTPS
Relative paths and HTTP URLs are both ignored:
<!-- Correct -->
<meta property="og:image" content="https://example.com/images/preview.jpg">
<!-- Won't work: relative URL -->
<meta property="og:image" content="/images/preview.jpg">
<!-- Won't work: HTTP instead of HTTPS -->
<meta property="og:image" content="http://example.com/images/preview.jpg">
Fallback behavior
Missing og:title falls back to <title>. Missing og:description may fall back to <meta name="description">, though this varies by Signal version. If no title exists at all, Signal may show just the domain name.
Without og:image, you get a text-only preview.
No Twitter Card support
Signal ignores Twitter Card tags entirely (twitter:title, twitter:description, twitter:image). If your site only has Twitter Card tags, Signal won’t pick them up. Always include standard OG tags.
Recommended minimal setup
These three tags are both the minimum and effectively the maximum. Nothing else improves Signal previews:
<meta property="og:title" content="Your Page Title">
<meta property="og:description" content="A brief description of the page content.">
<meta property="og:image" content="https://example.com/images/preview.jpg">