Free Link Preview Checker — Test Any URL Before You Share It

Last updated: April 2026 7 min read

What a Link Preview Checker Does
How to Use the Free Link Preview Checker
Most Common Link Preview Failures
Platform-by-Platform Preview Rules
How to Fix Broken Previews
When to Run a Preview Check
Frequently Asked Questions

You post a link and the preview looks completely wrong. The image is missing, the title is truncated, or a random image from the page showed up instead of the one you intended. By the time you notice, the post is already live.

A link preview checker shows you exactly what Facebook, LinkedIn, Twitter, and other platforms will display before you share anything. Paste your page HTML and see the preview card rendered in seconds — no platform login, no waiting for caches to update.

This guide covers how link preview checkers work, the most common reasons previews break, and how to fix them before they go public.

What a Link Preview Checker Does

When someone shares a URL on social media, the platform fetches your page and reads specific meta tags from the HTML to build a preview card. The card shows a thumbnail image, a title, and a short description. A link preview checker reads those same tags and renders what the card will look like.

The tags it looks for are called Open Graph tags. They were created by Facebook and are now used by every major platform: LinkedIn, Twitter/X, Slack, Discord, WhatsApp, and iMessage all read og:title, og:description, and og:image to generate their previews.

Tags that control link previews

og:title — the headline shown in the card
og:description — the short text below the title
og:image — the thumbnail URL
og:url — the canonical page URL
twitter:card — sets the Twitter card format (summary or summary_large_image)
twitter:image — a separate image for Twitter if needed

If any of these are missing or wrong, the preview breaks. A checker catches that before the share happens.

How to Use the Free Link Preview Checker

The tool has two input methods. Pasting HTML is the most reliable — it works for any page regardless of CORS settings, staging environments, or login walls.

Method 1: Paste HTML source (recommended)

Open your page in a browser
Press Ctrl+U (Windows) or Cmd+U (Mac) to view the source
Select all with Ctrl+A, then copy with Ctrl+C
Paste into the HTML tab in the checker
Click Check Tags

The checker processes everything in your browser. Nothing is sent to a server. This method works for localhost, staging URLs, and any page you can open in a tab.

Method 2: Enter a URL

Paste your live URL into the URL field
Click Check Tags

URL fetching depends on whether the target site allows cross-origin requests. Some sites block them entirely. If you get a fetch error, switch to the HTML paste method.

Reading the results

Results are organized in three sections: Basic SEO (title tag, meta description), Open Graph tags, and Twitter Card tags. Each tag shows its current value and a status. The recommendations panel flags anything missing. Below that, rendered preview cards show what Facebook/LinkedIn and Twitter/X will actually display.

Most Common Link Preview Failures

These are the problems that show up most often in a link preview check.

Missing og:image

No image tag means platforms either show nothing or grab a random image from the page body. Add an og:image tag pointing to a 1200x630 pixel image at an absolute HTTPS URL. Relative URLs like /images/preview.jpg will not work — platforms need the full URL to fetch from their servers.

Image is too small

Facebook requires at least 200x200 pixels to show any image. For the large card format that fills the full width of the feed, you need at least 1200x630. Smaller images render as a tiny square beside the text instead of a featured thumbnail.

Description over the limit

Facebook shows up to 300 characters. LinkedIn shows less. Twitter wraps at about 200 characters. Keep og:description under 155 characters to display cleanly everywhere.

Tags present but not in the head

Open Graph tags only work inside the <head> element. If a CMS or framework is injecting them into the body, platforms will not find them.

Old preview stuck in cache

You fixed the tags but the platform still shows the broken preview. This is a caching issue on the platform side. Each platform has a debug tool that forces a re-scrape — see the fixing section below.

Platform-by-Platform Preview Rules

Every platform reads the same Open Graph tags but applies its own image cropping, character limits, and caching rules.

Facebook

The default card shows a thumbnail beside the text. The large card format (which fills the feed width) needs an image at 1.91:1 ratio, minimum 1200x630. Facebook caches previews aggressively. Use the Sharing Debugger at developers.facebook.com/tools/debug to force a refresh after updating tags.

LinkedIn shows a standard card with image on the left and text on the right in feeds, or a large banner image in article posts. Use the Post Inspector at linkedin.com/post-inspector to force LinkedIn to re-fetch your page.

Twitter / X

Set twitter:card to summary_large_image for a full-width preview image. Without it, you get the small summary format with a square thumbnail. Twitter falls back to og: tags if twitter:-specific tags are absent.

Slack and Discord

Both read standard OG tags and render a compact card with an image thumbnail. Discord sometimes shows a different crop than expected — check og:image dimensions specifically. Discord also has a developer mode that shows the raw embed data for any link.

WhatsApp uses og:title, og:description, and og:image. Images must be at least 300x200 pixels. WhatsApp caches previews on its own infrastructure, so updates may not appear immediately for previously shared URLs.

How to Fix Broken Previews

After the checker identifies what is missing or wrong, fixing it takes a few minutes.

Add the missing tags

Open Graph tags belong in the <head> section of your HTML. Here is the minimum set every page needs:

<meta property="og:title" content="Your Page Title" />
<meta property="og:description" content="Short description under 155 characters." />
<meta property="og:image" content="https://yourdomain.com/og-preview.jpg" />
<meta property="og:url" content="https://yourdomain.com/page/" />
<meta property="og:type" content="website" />
<meta name="twitter:card" content="summary_large_image" />

If you use a CMS like WordPress or Webflow, these fields are usually available in the page SEO settings or through a plugin — you do not need to edit HTML directly.

Clear platform caches after updates

After updating your tags, platforms still show the old cached preview until you force a refresh:

Facebook: developers.facebook.com/tools/debug — click "Scrape Again"
LinkedIn: linkedin.com/post-inspector — click "Inspect"
Twitter: cards-dev.twitter.com/validator — enter your URL

After forcing a re-scrape, run the page through the link preview checker one more time to confirm everything reads correctly.

When to Run a Preview Check

Building a preview check into your publishing workflow prevents broken previews from ever going live.

Before publishing any content you plan to share

Blog posts, landing pages, product pages — anything that will be linked from social media or email campaigns. Check it before it goes live.

After a CMS migration or template change

Platform migrations frequently break meta tag output. A new theme or template may not wire up the OG tag fields the same way as the old one. Spot-check several page types after any migration.

When setting up a new page template

If you are building a new page type that will be replicated hundreds of times, check one instance first. A missing tag in the template means every page generated from it will have the same problem.

Before paid campaigns with a landing page

Paid traffic often generates organic shares from visitors who found the page through your ad. Make sure the landing page has solid OG tags so those organic shares look professional.

The full workflow — view source, paste HTML, check results, fix anything flagged — takes under two minutes. It is worth making a standard step before any publish.

Try It Free — No Signup Required

Runs 100% in your browser. No data is collected, stored, or sent anywhere.

Open Free OG Tag Checker

Frequently Asked Questions

Why does the preview checker show correct tags but Facebook still shows the wrong preview?

Facebook caches previews heavily. Once a URL is scraped, the cached version can persist for days. Use Facebook's Sharing Debugger at developers.facebook.com/tools/debug, enter your URL, and click "Scrape Again" to force a fresh fetch. After that, the checker and Facebook should match.

Can I check a page that is not live yet?

Yes. Use the HTML paste method. Open the page in your local browser, press Ctrl+U to view the source, copy all of it, and paste it into the checker. It reads the meta tags directly from the HTML without making any network request, so it works on localhost, staging servers, or any page protected by a login.

My og:image URL looks correct but the checker says the image is missing. Why?

Platforms require an absolute URL starting with https:// for og:image. A relative path like /images/preview.jpg will not work. Make sure the og:image value is the full URL including the domain: https://yourdomain.com/images/preview.jpg.

Does using this checker send my HTML to any server?

No. The tool runs entirely in your browser using the browser's built-in HTML parser. Your HTML is never sent anywhere. This makes it safe to use with staging pages, internal tools, or any content you have not published yet.