How to use the Open Graph Checker
- Paste the URL you plan to share and click Check tags.
- Compare the Facebook/LinkedIn, X and Slack previews — they show what each platform would build from your tags.
- Look for red “missing” badges in the tag tables and check that the og:image loads with the recommended size.
- Copy the generated snippet for missing tags into your page’s
<head>, then re-scrape the URL on each platform.
What is an Open Graph checker?
When a link is shared on Facebook, LinkedIn, Slack, WhatsApp, Discord and most other apps, the platform fetches the page and builds a preview card from its Open Graph meta tags — a protocol originally created by Facebook. X (formerly Twitter) uses its own twitter:* tags but falls back to Open Graph where they are missing. An Open Graph checker fetches your page the same way and shows the tags it finds and the cards they would produce, so you can fix a broken preview before anyone shares it.
The tags every page should have
| Tag | Purpose |
|---|---|
og:title | Headline of the card. Can be more conversational than the SEO title. |
og:description | One or two sentences under the headline. |
og:image | Absolute URL of the preview image — the single biggest factor for clicks. |
og:url | Canonical URL, so shares of variants are counted together. |
og:type | Usually website or article. |
twitter:card | summary_large_image for a big image, summary for a small square thumbnail. |
Recommended extras are og:site_name, og:locale, og:image:alt (describes the image for screen readers) and og:image:width/og:image:height, which let some platforms render the card before downloading the image.
Image size recommendations
- 1200 × 630 px (1.91 : 1) works well for Facebook, LinkedIn and Slack. Keep important text away from the edges, as some apps crop to a square or 2 : 1.
- X large card: 2 : 1 aspect ratio, at least 300 × 157 px, under 5 MB. A 1200 × 630 image displays with slight cropping.
- Use JPEG or PNG for the widest support, an absolute
https://URL, and make sure the image isn't blocked by robots.txt or a login.
Need an image? Create one with the OG Image Generator.
Why does my old preview still show?
Platforms cache previews, often for days. After fixing tags, ask each platform to re-fetch: Facebook's Sharing Debugger (“Scrape Again”), LinkedIn's Post Inspector, and for Slack simply share the URL with a harmless query string such as ?v=2. Also check that the page doesn't block crawlers and that the tags are in the server-rendered HTML — most scrapers do not execute JavaScript. To write a full tag set from scratch, use the Meta Tag Generator.
Tools that pair well with the Open Graph Checker
- SEO Checker & Site Audit — Paste a URL to run up to 70 on-page SEO checks in seconds.
- Schema Markup Validator — Test the structured data on any URL or paste your JSON-LD to find syntax errors, missing required properties and recommended fields for Google rich results.
- Heading Checker — Visualise the heading outline of any page.
- Image Alt Checker — Audit every image on a page in one table: alt text status, file size, width/height attributes, format and lazy loading — with filters and CSV export.
Frequently asked questions
What is the best og:image size?
Do I need Twitter Card tags if I have Open Graph tags?
twitter:card is really needed: X falls back to og:title, og:description and og:image. Add twitter:card with summary_large_image to get the large image layout.