# Sharelint

> The link preview linter: see, score and fix how a URL looks in 12 apps, messaging apps included.

Free link preview checker. See how any URL looks when shared on Facebook, WhatsApp, X, Telegram, LinkedIn, iMessage, Discord, Slack, Messenger, Instagram, Snapchat and TikTok, with per-platform fixes for Open Graph and Twitter Card tags.

The checker fetches a public URL with each platform’s real crawler User-Agent, parses the raw HTML head (no JavaScript, like the crawlers), downloads the preview images to read their size and dimensions, and reports per-platform layouts and problems.

## API

- [Markdown report](https://sharelint.pages.dev/api/preview?format=md&url=https://example.com): `GET /api/preview?url=<url>&format=md`. Returns a Markdown report with a score, page-wide issues, a per-platform table and the meta tags found. Best for LLM agents and pull-request comments.
- [JSON report](https://sharelint.pages.dev/api/preview?url=https://example.com): `GET /api/preview?url=<url>`. Returns { result, pageIssues, platforms[], score }.
- [OpenAPI spec](https://sharelint.pages.dev/openapi.json): full schema. Optional `crawler` parameter: facebook, whatsapp, twitter, telegram, linkedin, discord, slack, imessage, browser.

## Platform guides

- [Facebook link preview checker](https://sharelint.pages.dev/facebook-link-preview.md): Facebook builds link cards from Open Graph tags fetched by facebookexternalhit. The same cache is shared by Messenger and Instagram DMs.
- [WhatsApp link preview checker](https://sharelint.pages.dev/whatsapp-link-preview.md): WhatsApp generates previews on the sender’s device from the og: tags, and is strict about image weight and format.
- [X (Twitter) card validator alternative](https://sharelint.pages.dev/twitter-card-validator.md): 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.
- [Telegram link preview checker](https://sharelint.pages.dev/telegram-link-preview.md): Telegram shows og:site_name as a coloured header, then the title, description and image.
- [LinkedIn link preview checker](https://sharelint.pages.dev/linkedin-link-preview.md): LinkedIn shows the og:title, image and domain. Descriptions are no longer shown in the feed.
- [iMessage link preview checker](https://sharelint.pages.dev/imessage-link-preview.md): iMessage fetches the page from the sender’s device and shows only the title, domain and image or icon.
- [Discord embed preview checker](https://sharelint.pages.dev/discord-embed-preview.md): Discord renders an embed coloured by theme-color, with the site name, title, description and image.
- [Slack unfurl preview checker](https://sharelint.pages.dev/slack-unfurl-preview.md): Slackbot unfurls links using the favicon, og:site_name, title, description and image.
- [Messenger link preview checker](https://sharelint.pages.dev/messenger-link-preview.md): Messenger uses the Facebook crawler and cache, shown as a rounded chat card.
- [Instagram link preview checker](https://sharelint.pages.dev/instagram-link-preview.md): Instagram only shows link cards in direct messages. Links in captions are not clickable.
- [Snapchat link preview checker](https://sharelint.pages.dev/snapchat-link-preview.md): Snapchat shows a compact card with a thumbnail, title and domain in chats and Snap attachments.
- [TikTok link preview checker](https://sharelint.pages.dev/tiktok-link-preview.md): TikTok shows minimal link previews, and only in DMs. Links in captions are plain text.

## Optional

- [Full guide text](https://sharelint.pages.dev/llms-full.txt): every platform guide plus the FAQ in one file