{ "as_of": "26 Oct 2026", "note": "From docs, developer reports and device tests.", "platforms": [ { "platform": "iMessage", "status": "plays", "note": "Autoplays the MP4 muted, looping. With autoplay off or Reduce Motion: poster with a play button. Apple's guidelines: the page itself under 1 MB; icon, image and video together under 10 MB. A video that can only be streamed (HLS) needs a tap. Device-tested 24 Oct 2026. Without og:image: a text bubble with the title, the domain and the site icon (seen 24 Oct 2026).", "source": "https://developer.apple.com/documentation/technotes/tn3156-create-rich-previews-for-messages", "source_date": "2024-04" }, { "platform": "Discord", "status": "plays", "note": "Inline player with a play button; does not autoplay. Device-tested 24 Oct 2026 on the Mac and iOS clients with a plain og:type website page and a direct MP4. Discord's docs only describe og:type video.* or twitter:card player; neither was needed. Without any og: or twitter: tags: no embed at all, just the link (device-tested 24 Oct 2026, Mac and iOS, on a page with only a and meta description). Discord's docs say the <title> and meta description are used as a pair when there are no title and description tags; re-test. Discord's docs: MP4, WebM or MOV; the fetch returns at most 50 MB and must finish, measuring the image and video included, within 10 seconds.", "source": "https://docs.discord.com/developers/link-previews/overview", "source_date": "n.d.", "refresh": "Caches previews for about 30 minutes; until then, resharing the same URL shows the old card. Share it with a new query string such as ?v=2, or look it up in the Embed Debugger (discord.com/developers/embeds).", "refresh_source": "https://docs.discord.com/developers/link-previews/overview" }, { "platform": "Telegram", "status": "poster", "note": "Shows og:image. Tested 24 Oct; FxEmbed's claim that it plays did not hold.", "source": "https://docs.fxembed.com/guide/getting-started/", "source_date": "2026-09" }, { "platform": "X (Twitter)", "status": "poster", "note": "Link cards show og:image. The viral og:video posts were iMessage screen recordings. The large card needs twitter:card=summary_large_image; otherwise a small card with a square thumbnail. Without og:image: the small card with a placeholder; without any og: or twitter: tags: no card. On the large card X overlays the title in a dark strip at the bottom-left of the image and puts the domain under the card as 'From domain' (measured on x.com at desktop and 390 px phone widths, 24 Oct 2026).", "source": "https://x.com/pfista/status/2113599976714743874", "source_date": "2026-10" }, { "platform": "WhatsApp", "status": "poster", "note": "Uses og:image as the thumbnail; og:video not mentioned.", "source": "https://developers.facebook.com/documentation/business-messaging/whatsapp/link-previews", "source_date": "n.d." }, { "platform": "Slack", "status": "poster", "note": "Classic unfurls read Open Graph and Twitter Card tags and show og:image; video players only for sites Slack handles itself, or through an app unfurl.", "source": "https://docs.slack.dev/messaging/unfurling-links-in-messages/#classic_unfurl", "source_date": "n.d.", "refresh": "Caches each URL across the service for about 30 minutes and documents no way to clear it. Wait that long, or share the link with a new query string such as ?v=2.", "refresh_source": "https://api.slack.com/robots" }, { "platform": "Bluesky", "status": "poster", "note": "Link cards carry a title, description and one thumbnail (app.bsky.embed.external); there is no video field.", "source": "https://docs.bsky.app/docs/advanced-guides/posts#website-card-embeds", "source_date": "n.d.", "refresh": "The card is saved into each post when it's written, so a post keeps its card; a new post fetches the page again.", "refresh_source": "https://docs.bsky.app/docs/advanced-guides/posts#website-card-embeds" }, { "platform": "Mastodon", "status": "poster", "note": "Video cards come from oEmbed, not og:video.", "source": "https://docs.joinmastodon.org/entities/PreviewCard/", "source_date": "n.d." }, { "platform": "Signal", "status": "poster", "note": "Shows og:image with the title and description; no video.", "source": "https://support.signal.org/hc/en-us/articles/360022474332-Link-Previews", "source_date": "n.d." }, { "platform": "LinkedIn", "status": "poster", "note": "Reads og:image, title, description; no video seen.", "source": "https://www.linkedin.com/post-inspector/", "source_date": "n.d." }, { "platform": "Matrix / Element", "status": "poster", "note": "Element shows the title, description and og:image that the homeserver's URL preview endpoint returns; no og:video support.", "source": "https://spec.matrix.org/latest/client-server-api/#get_matrixclientv1mediapreview_url", "source_date": "n.d." }, { "platform": "Facebook", "status": "poster", "note": "Shows og:image. Tested 24 Oct; docs say an MP4 is only 'eligible' for inline play. Without og:image: a text card with the domain and title (Sharing Debugger, 24 Oct 2026).", "source": "https://developers.facebook.com/documentation/sharing/webmasters", "source_date": "n.d.", "refresh": "Paste the URL into the Sharing Debugger (developers.facebook.com/tools/debug); it scrapes the page again. Images are cached by URL and don't update unless the image URL changes.", "refresh_source": "https://developers.facebook.com/documentation/sharing/webmasters" } ], "untested": [ "Messenger", "Instagram DMs", "Threads", "Reddit", "Teams", "Google Chat", "Pinterest", "Tumblr", "Snapchat", "WeChat", "Line", "Viber" ], "refresh": { "tip": "Apps cache a preview by its URL, so after you fix the tags an app can keep showing the old card. Share the link with a new query string, such as ?v=2, and give a changed og:image or og:video file a new URL too.", "source": "https://docs.discord.com/developers/link-previews/overview" } }