| Image size | 1200x627px |
| Aspect ratio | 1.91:1 |
| Max file size | 5 MB |
| Formats | image/jpeg, image/png, image/webp, image/gif |
| User-Agent | Mozilla/5.0 AppleWebKit/537.36 (KHTML, like Gecko; compatible; Bluesky Cardyb/1.1; +mailto:support@bsky.app) Chrome/W.X.Y.Z Safari/537.36 |
Bluesky is built on the AT Protocol, a decentralized social networking protocol. Link card data is fetched by a service called CardyB and then baked permanently into the post record, making Bluesky’s caching model fundamentally different from every other platform.
This guide covers how CardyB crawls your pages, which tags Bluesky reads, image compression requirements, the immutable caching model, and the most common issues that prevent cards from displaying correctly.
Understanding CardyB and Bluesky's client-side link card architecture
Which meta tags Bluesky reads and how they map to AT Protocol records
Image sizes, compression requirements, and format support for Bluesky cards
Why Bluesky card data can never be updated after posting
Troubleshooting the most frequent Bluesky link card problems
Enter your site's URL to see how it looks on Bluesky.