Help Centre

Last updated: August 7, 2026

Getting started

Previewcard is a URL inspection tool. Paste a link, and it shows you how that link will look when shared on LinkedIn, Twitter (X), Facebook, and Slack — plus a full diagnostic breakdown of every Open Graph and Twitter Card tag on the page.

Go to the App page.

Paste any URL into the input field and click Check preview.

Wait a few seconds while Previewcard fetches the page, parses the meta tags, resolves the image URL, and fetches the image to confirm it resolves and measure its dimensions.

Review the rendered card preview and the tag-by-tag diagnostic list below it. Tags are marked OK, MISSING, or ERROR.

No sign-up, no account, no email required. The tool is free to use for single URL checks.

Frequently asked questions

My link has no preview image on Slack / LinkedIn / Twitter — what's wrong?

The most common causes, in order of likelihood:

Missing og:image tag. The page has no Open Graph image meta tag at all. Previewcard will show this tag as MISSING. Add an <meta property="og:image" content="..."> tag to your page's <head>.
Relative image path. The og:image value is a relative URL like /images/hero.png instead of an absolute URL like https://example.com/images/hero.png. Social platforms cannot resolve relative paths the way a browser does. Previewcard resolves it for you and reports the resolved URL — look for the warning.
Image too small. LinkedIn requires at least 200×200 pixels; Twitter's summary_large_image card prefers 1200×630; Slack scales poorly below 400×200. Previewcard fetches the image and reports its real dimensions.
Image returns a 404 or 403. The tag exists but the URL points at a page that doesn't exist or blocks the fetch. Previewcard reports the HTTP status.

Run the URL through Previewcard first — it will tell you exactly which of these problems exists, rather than guessing.

Does Previewcard work with any URL?

Previewcard works with any publicly accessible URL that returns an HTML page. It does not work with:

Pages behind a login or firewall (returns a "could not fetch" error).
Non-HTML resources (PDFs, images, JSON endpoints — no meta tags to parse).
URLs that redirect to a login page (the tool will report what the login page's meta tags say, not the intended page's tags).
Very large or slow pages (the server has a timeout and will report the check did not complete).

If the page cannot be fetched at all, Previewcard says so explicitly and does not report the fetch failure as a finding about your tags.

Why does the preview in Previewcard look different from what I see on the actual platform?

A few factors are outside Previewcard's control:

Platform caching. LinkedIn, Twitter, and Facebook cache a page's Open Graph data for hours or days after the first share. Even after you fix your tags, the old preview may persist until the platform re-fetches. Use their individual debugger tools (LinkedIn Post Inspector, Twitter Card Validator, Facebook Sharing Debugger) to request a re-crawl.
Platform-specific fallback logic. Each platform handles missing tags differently — some fall back to the HTML <title>, some use the first <h1>, some show nothing. Previewcard reports which tags are present (not which platform's fallback is triggered).
Image cropping. Platforms crop images to different aspect ratios. Previewcard shows the raw image at its natural dimensions and reports the measured width and height so you can decide if it fits the platform's requirements.

Previewcard reads the tags the same way a platform does on first fetch. The display difference is usually caused by the platform using cached data rather than re-fetching.

Do you store the URLs I check? Is my data private?

Previewcard is intentionally stateless:

No accounts, no sign-ups, no logins. There is no place for data to be associated with you.
No database. The tool fetches your URL, produces a result, sends it back to your browser, and retains nothing. When you close the tab or navigate away, the result is gone.
No analytics scripts or tracking cookies. Google Fonts is loaded from Google's servers for typography; Google's privacy policy applies to that request.
No server-side logging of IP addresses, user agents, or URLs checked.

See the full Privacy Policy for details.

The tool says a tag is missing. What should I do?

The diagnostic section lists every tag it checks and marks each as OK, MISSING, or ERROR. Here is what to do for the most common missing tags:

og:title missing: Add <meta property="og:title" content="Your Page Title">. This is what LinkedIn and Facebook show as the headline. It should be 40–60 characters.
og:description missing: Add <meta property="og:description" content="A 1–2 sentence summary of this page">. Aim for 80–160 characters. Platforms may truncate beyond that.
og:image missing: Add <meta property="og:image" content="https://example.com/path/to/image.jpg">. Use an absolute URL. The image should be at least 1200×630 pixels for best results.
twitter:card missing: Add <meta name="twitter:card" content="summary_large_image"> to get the large image preview on Twitter/X. Without it, Twitter uses a minimal text-only card.

All these tags go inside the <head> section of your HTML page. After adding them, run the URL through Previewcard again to confirm they are recognised.

What image dimensions should my og:image be?

The recommended dimensions vary by platform, but 1200×630 pixels is the safe standard that works everywhere:

LinkedIn: 1200×627 (or at least 200×200, max 20 MB). The preview image is cropped to roughly 1.91:1 aspect ratio.
Twitter (summary_large_image): 1200×600 (2:1 ratio). Minimum 300×157, maximum 4096×4096.
Facebook: At least 600×315; 1200×630 recommended. 1.91:1 aspect ratio.
Slack: No published minimum, but images under 400×200 tend to render very small. Larger images at 16:9 or 1.91:1 work well.

Previewcard fetches your image and reports its actual width and height so you can compare against these numbers.

Can I check multiple URLs at once? Do you have an API?

Not yet. Currently Previewcard checks one URL at a time through the web interface. Batch URL checking and API access are planned features listed on the Pricing page but are not yet available for purchase.

There is no account system, so there is no saved check history or the ability to return to a previous result. Every check is independent and ephemeral.

Known limitations

Honest about what is not built yet. Previewcard is an early-stage tool. The following limitations exist today:

No email support. There is no mailbox on any domain in this fleet. If a page says "email us," that inbox does not exist. The only contact route is described below.
No accounts, no history, no saved checks. Every check is ephemeral. If you reload the page, the result is gone.
No batch checking. One URL at a time, always.
No API. There is no programmatic endpoint. All checking is done through the web interface.
No Pro plan yet. The Pro subscription and checkout form on the Pricing page are demonstrations. No real payment is taken and Pro features are not available.
No legal entity. The product is operated by an individual who has not registered a company or appointed a representative. There is no jurisdiction or governing law claimed.
No compliance certifications. Previewcard does not claim compliance with any standard, certification, or audit regime.
No rendering guarantee. Platforms change their rendering behaviour, apply different fallback logic, and cache older versions of pages. Previewcard reports the tags as they are — it does not guarantee the preview matches what any platform will ultimately show.
Timeout on slow pages. If the target page is very slow or very large, the check may time out and report "check did not complete."

How to contact us

Support is not yet reachable by email. There is currently no mailbox, email address, or postal address associated with this product. The operator has not registered a legal entity or appointed a support representative.

If you need to report a problem with the tool — a URL that should work but does not, a tag that is misreported, or a suggestion — the best way is to document what you observed and note this in needs.md in the project root. The operator reviews this file periodically.

For urgent issues affecting your ability to use the tool, we recommend refreshing the page and trying again. The tool is stateless, so no data is lost by reloading.

A proper contact method — email address or support channel — will be added when a legal entity is registered.