Link preview checker for 12 apps
Check every share before it ships.
Paste a URL to preview its share card on Facebook, WhatsApp, X, Telegram, LinkedIn, iMessage, Discord, Slack, Messenger, Instagram, Snapchat and TikTok. You get exact fixes for your Open Graph and Twitter Card tags.
How it works
Link previews are built by each platform's crawler, which downloads your page's raw HTML and reads its meta tags
without running JavaScript. This checker does the same: it fetches your page with the real crawler User-Agent,
follows redirects, parses og: and twitter: tags, downloads the preview image to measure
its dimensions and weight, and applies each platform's own rules for layout, fallbacks and limits.
Supported platforms
- FacebookFacebook builds link cards from Open Graph tags fetched by facebookexternalhit. The same cache is shared by Messenger and Instagram DMs.
- WhatsAppWhatsApp generates previews on the sender’s device from the og: tags, and is strict about image weight and format.
- X (Twitter)X reads twitter: tags first and falls back to Open Graph. X retired its official Card Validator preview, so you need another way to check cards.
- TelegramTelegram shows og:site_name as a coloured header, then the title, description and image.
- LinkedInLinkedIn shows the og:title, image and domain. Descriptions are no longer shown in the feed.
- iMessageiMessage fetches the page from the sender’s device and shows only the title, domain and image or icon.
- DiscordDiscord renders an embed coloured by theme-color, with the site name, title, description and image.
- SlackSlackbot unfurls links using the favicon, og:site_name, title, description and image.
- MessengerMessenger uses the Facebook crawler and cache, shown as a rounded chat card.
- InstagramInstagram only shows link cards in direct messages. Links in captions are not clickable.
- SnapchatSnapchat shows a compact card with a thumbnail, title and domain in chats and Snap attachments.
- TikTokTikTok shows minimal link previews, and only in DMs. Links in captions are plain text.
API for CI, scripts and AI agents
Every check is available as plain HTTP, with no key needed. Ask for Markdown to get a report you can paste into a pull request or hand to an LLM.
curl "https://sharelint.pages.dev/api/preview?url=https://example.com&format=md"See openapi.json for the schema and llms.txt for an LLM-ready summary of this site.
Frequently asked questions
Why does my link show no preview, or the wrong image?
Platforms build previews from the og:title, og:description and og:image tags in the raw HTML of your page. Their crawlers do not run JavaScript, so tags added by client-side code are invisible to them. The image must be an absolute URL, publicly reachable, and within each platform’s size and format limits.
Why does WhatsApp not show my og:image?
WhatsApp skips images that are too heavy (keep them under 300 KB, and never above about 600 KB), served over plain http, or in formats such as SVG or AVIF. Use a 1200×630 JPEG or PNG and an absolute https URL.
How do I refresh a cached preview?
Facebook, Messenger and Instagram: use the Facebook Sharing Debugger and click Scrape Again. LinkedIn: use Post Inspector. Telegram: send the link to @WebpageBot. X, WhatsApp, iMessage, Discord and Slack have no public refresh tool, so add a query string such as ?v=2 to make them treat it as a new URL.
What image size works on every platform?
A 1200×630 pixel JPEG or PNG under 300 KB, served from an absolute https URL, with og:image:width and og:image:height set. Keep important content in the centre, because square and small layouts crop the sides.
Can I check localhost or a staging site behind a login?
Not yet. The checker fetches pages from the public internet, like the real crawlers. Deploy a public preview URL, or use the browser extension when it ships.
Is there an API for scripts, CI and AI agents?
Yes. GET /api/preview?url=<url> returns JSON. Add format=md to get a Markdown report that is easy to paste into a pull request or hand to an LLM. See /llms.txt and /openapi.json.