Generate Twitter Card Images with an API
A Twitter (X) card image is the large preview shown when a link is shared on X. FastOG generates it dynamically at 1200×630 and signals summary_large_image, so every page gets a proper X card without creating an image by hand.
What a Twitter card image needs
X reads Open Graph tags and renders a summary_large_image card when the page links twitter:card = summary_large_image. The image renders at 1200×630. FastOG produces exactly that, and you point twitter:image at the same dynamic URL as og:image.
How to wire a dynamic Twitter card
Generate your FastOG URL once, then set both the OG and Twitter meta tags to it.
<meta property="og:image" content="https://fastog.com/api/v1/og?template=default&title=My+Post&key=sk_...&s=...">
<meta name="twitter:card" content="summary_large_image">
<meta name="twitter:title" content="My Post">
<meta name="twitter:image" content="https://fastog.com/api/v1/og?template=default&title=My+Post&key=sk_...&s=...">
The same URL works for both tags. X falls back to
og:imageiftwitter:imageis absent, but setting both is harmless and explicit.
X Card validator tips
| Check | Detail |
|---|---|
| Public URL | The image must be fetchable by X without auth |
| File size / format | Keep under 5 MB; PNG is best for text cards |
| Cache | X caches aggressively — use the Card Validator to force a refresh |
| Signed URLs | FastOG's content-signed URLs only gate the first render; cached cards stay valid |
FAQ
Do I need separate images for X and Open Graph?
No. X reads the same 1200×630 image. This page exists because the correct twitter:card tags are easy to get wrong.
Why is my X card not updating after I change the title?
X caches the old card. Open the X Card Validator, paste the URL, and re-scrape.
Does FastOG handle the twitter meta tags too?
FastOG generates the image; you still add the twitter:card and twitter:image meta tags to your page (as shown above). Our free Open Graph Meta Tag Generator writes all the tags for you.
Related
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