Social Preview Checker: Preview Your Facebook & Zalo Share

Social Preview Checker shows you exactly how your link will look when someone pastes it into Facebook, Zalo, or Twitter/X — before you actually share it. It reads the Open Graph tags, Twitter Card meta, and hreflang links straight from your page, then rebuilds the preview the way each platform would.

Why your shared link looks embarrassing on social media

This is a familiar situation: you paste a product link into a group chat, and instead of a nice product photo, the preview grabs your header logo or some random icon from the page. The reason is simple — Zalo, Facebook and Twitter don't read a page the way a human does. They only look at a handful of specific meta tags (Open Graph), and when those are missing, they guess by grabbing the first image or text they find in the HTML.

Open Graph: the brain behind every preview

Four tags matter most: og:title (the headline shown), og:description (a short summary), og:image (the preview picture), and og:url (the canonical URL, which prevents duplicate previews when people share slightly different variations of the same page). A missing og:image is the single most common mistake — and the most obvious one, since the preview ends up looking bare and unprofessional.

Twitter Card doesn't automatically piggyback on Open Graph

A lot of people assume Open Graph tags cover every platform. Twitter/X actually has its own tag set (twitter:card, twitter:title, and so on) and only falls back to Open Graph when Twitter-specific tags are completely absent. If you want precise control over how your link appears on Twitter — say, forcing the large "summary_large_image" format instead of the small default thumbnail — you need to declare it separately.

What size should og:image actually be

Facebook recommends at least 1200×630px at a 1.91:1 ratio. Smaller images still display, but they tend to look blurry or get cropped in the wrong spot, like cutting off a person's face in a product photo.

hreflang: a problem unique to multilingual sites

If your site has both a Vietnamese and an English version, hreflang tells Google which version to show to which language or region. Get it wrong or leave it out, and Google may treat the two versions as duplicate content, or serve the English page to a Vietnamese visitor by mistake.

Preview your link right now

Paste a URL into the free Social Preview Checker to see a simulated preview, a full OG/Twitter Card checklist, and every declared hreflang pair — all in one scan.

Conclusion

A good preview won't move your SEO ranking, but it does decide whether someone actually clicks your link or scrolls right past it. Spending two minutes checking before you share an important post or campaign is worth it.