Twitter Card validator: preview your Twitter/X link cards
Twitter retired its official Card Validator, leaving creators, marketers, and developers with no easy way to preview Twitter/X link cards before posting. This free Twitter Card validator is a drop-in replacement: paste any URL, and we fetch it using Twitterbot's exact user-agent string to show you the raw HTML Twitter/X receives.
We extract every Twitter Card tag (twitter:card, twitter:title, twitter:description, twitter:image) and the Open Graph fallbacks, then render a pixel-accurate preview of how your card will appear in a tweet. If tags are missing or injected client-side by a JavaScript framework, you will see it immediately - before the broken card goes live on your timeline.
No signup, no developer account, no waitlist. Validate your Twitter Card below.
How to use this tool
- 1
Choose a crawler from the list below (or select one from the category tabs)
- 2
Enter your page URL in the input field
- 3
Click 'Simulate crawl' to fetch your page with that bot's user agent
- 4
Review the HTML response - check for your page title, main content, and meta tags
- 5
Test multiple crawlers to compare how each one sees your site
How it works
When you select a crawler and enter a URL, we send a server-side HTTP request using that bot's exact User-Agent string. For example, selecting Googlebot sends the request with 'Mozilla/5.0 (compatible; Googlebot/2.1)' - the same identifier Google's real crawler uses.
Your web server receives this request and responds based on the User-Agent. If you have dynamic rendering, cloaking rules, or bot-specific logic configured, the response will reflect that. This is exactly what happens during a real crawl - we are replicating the full request/response cycle.
The returned HTML is then analysed for SEO elements: title tag, meta description, Open Graph tags, heading structure, canonical URL, structured data, and overall text content. Each element is scored, and the tool flags missing or problematic items with severity ratings.
When you select multiple crawlers, each one makes an independent request in parallel. The results are displayed side by side in a comparison table so you can spot differences - for example, a page that returns complete HTML for Googlebot but an empty shell for GPTBot.
Understanding Twitter/X (Twitterbot)
When a link is shared on Twitter/X, Twitterbot fetches the page to generate a Twitter Card - the preview box that appears below the tweet showing a title, description, and image. Twitter Cards significantly increase engagement: tweets with cards receive substantially more clicks, retweets, and likes than plain text tweets with URLs.
Twitterbot does not execute JavaScript. It reads Twitter Card meta tags (twitter:card, twitter:title, twitter:description, twitter:image) and Open Graph tags as fallbacks from the raw HTML response. If your JavaScript framework injects these tags client-side, Twitterbot sees nothing and your tweets display as bare URLs.
Twitter/X supports several card types: summary (small image), summary_large_image (full-width image), player (embedded video), and app (mobile app install). The summary_large_image format is most commonly used and requires twitter:card set to 'summary_large_image' along with a twitter:image pointing to an image at least 300x157 pixels.
Pre-rendering ensures Twitterbot receives your Twitter Card and OG tags in the raw HTML, producing rich, visually engaging tweet cards that drive clicks and engagement.
Frequently asked questions
What is the difference between Twitter Cards and OG tags?▾
Twitter Card tags (twitter:title, twitter:description, twitter:image) are Twitter-specific. If they are missing, Twitterbot falls back to Open Graph equivalents (og:title, og:description, og:image). Best practice is to include both sets of tags.
What image size does Twitter require?▾
For summary_large_image cards: minimum 300x157 pixels, maximum 4096x4096, under 5MB. The recommended size is 1200x628 pixels. Images are cropped to a 2:1 aspect ratio.
How do I test my Twitter Card without tweeting?▾
Use this crawler simulator to check whether Twitterbot can see your meta tags. You can also use Twitter's Card Validator (cards-dev.twitter.com/validator) to preview the card, though availability of this tool varies.
Related crawler tests
Facebook debugger alternative
Preview how Facebook and Messenger display your shared links. Facebook's crawler reads Open Graph meta tags from the raw HTML - it does not execute JavaScript, so dynamically-injected OG tags will not appear.
Social mediaLinkedIn Post Inspector alternative
Check your link preview on LinkedIn. LinkedIn's crawler fetches raw HTML to build post previews. If your Open Graph tags are injected via JavaScript, LinkedIn will show a generic preview or no image at all.
Social mediaWhatsApp link preview debugger
Preview your link as it appears in WhatsApp messages. WhatsApp uses Facebook's crawler infrastructure and does not execute JavaScript. Missing OG tags mean no thumbnail, no title, and no description in chat.
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