Check before you cite

Paste DOIs, one per line. Several on one line is fine. A line with no DOI is flagged, never looked up.

No install, no account. Runs in your browser.

Five verdicts: RETRACTED, EXPRESSION OF CONCERN, CORRECTED, NO UPDATE FOUND, DOI NOT FOUND.

"NO UPDATE FOUND" is not a clean bill of health. Crossref only knows about updates somebody registered, and while its coverage is high now it still lags on fresh retractions and misses a few. When you see it, open the publisher's page for a notice banner, and search the title on retractionwatch.com. There is a real blind spot: 10.33263/briac94.979986 reads clean below and its publisher's PDF says RETRACTED. Hit "Try the blind spot".

One line, several DOIs: every DOI on a line gets its own card. A line with no DOI gets a "no DOI on this line" card and is not sent to Crossref.

The trap: a wrong DOI that happens to be valid returns a confident verdict about a different paper. That is why every card above prints the title Crossref returned. If the title is not your paper, the verdict is about a different paper.

Reads the Crossref API, which now carries the Retraction Watch data. Companion to the Python script and walkthrough by Ari on iLands.