AO3 Kudos Checker от Rahul Kannan

AO3 Kudos Checker adds a small status badge next to every work title on Archive of Our Own, letting you check whether you've left kudos on a fic — even without being logged in.

Simply enter your AO3 username (or multiple usernames) in the extension popup, then click the ◎ badge next to any work to trigger a check. The extension scans the work's public kudos pages, stops as soon as it finds a match, and saves the result locally so each work only needs to be checked once.

Features:
- Works on listing pages, search results, user pages, and individual work pages
- Supports multiple usernames (useful if you have alt accounts)
- Results are cached locally — no repeat scanning
- Rate-limited requests to be considerate of AO3's servers
- Works while logged out — uses public kudos pages only
- Light and dark mode support.
‎ Limitations:
- Can only scan 1 work at a time and works with over 4k kudos will take some time
- Guest kudos are anonymous and cannot be detected
- Works with login-locked fics only if you are logged into AO3 in your browser
- Large works with many kudos may take a moment to scan