Twitter card validator: what replaced Twitter's tool

For years the way to test a Twitter card was cards-dev.twitter.com/validator — paste a URL, see the render. Twitter shut it down in 2022, and under X it has never returned. The search volume for "twitter card validator" never went away, which is why this page exists: here is what to do instead.

Step 1: Confirm the tags are served

View the page source of your URL and look for twitter:card and the og: tags in the head. They must be in the served HTML — X's crawler does not run your client-side JavaScript.

<meta name="twitter:card" content="summary_large_image" />
<meta property="og:title" content="A headline under 60 characters" />
<meta property="og:description" content="One persuasive sentence, front-loaded." />
<meta property="og:image" content="https://example.com/card.png" />

Step 2: Check the image requirements

X needs an absolute https image URL, PNG or JPEG, at least 600x315 for the large card and under roughly 5 MB. An SVG, a relative path or an http URL each produce the classic broken card with an empty frame.

Step 3: Render the card

Without an official validator, the practical replacement is a preview tool that reads the same tags the same way. The Twitter Card validator page on this site renders the X card as it will appear in the timeline, grades the tags, measures the real image, and gives you the exact meta tag to add for anything missing.

The one tag that matters most

X falls back to your og: tags for title, description and image, but nothing falls back for twitter:card. If it is missing or set to summary, your image renders as a small square no matter how good it is. Set summary_large_image and the full-width card is yours.