How Manusights Sentry works

Crossref REST API

Primary source for paper metadata and update-to[] retraction notices

Sentry queries https://api.crossref.org/works/{DOI} with a mailto-identified User-Agent (polite pool, 50 req/s rate limit; effective Dec 1 2025). We run concurrency 3 to stay well under the limit with safety margin. The response includes:

• title, author, container-title, ISSN, publisher, issued.date-parts — for the per-reference card display
• update-to[] — the critical field. Array of update notices linked TO this work. Non-empty for retracted / EoC / corrected papers. Each entry carries a type (“retraction” / “expression-of-concern” / “correction” / etc.), the notice DOI, the notice label, and the registration timestamp.

Per-DOI responses are cached in Upstash Redis for 24 hours. Crossref data updates daily; retraction notices typically propagate within 24-72 hours of publication.

Reference: Crossref REST API documentation.

Retraction Watch dataset

ISSN: 2692-4579 · Fast-path retraction lookup with full reason metadata

Crossref Labs hosts the Retraction Watch dataset as a downloadable CSV with per-DOI retraction metadata. We mirror this nightly via a cron job into a Redis hash keyed by DOI, so retraction lookups are O(1) and don’t require an extra Crossref call. Fields used:

• OriginalPaperDOI — primary key, lowercase normalized
• RetractionNature — controlled vocabulary: “Retraction”, “Expression of Concern”, “Correction”, “Reinstatement”
• RetractionDate — ISO YYYY-MM-DD
• Reason — semicolon-separated controlled-vocabulary categories from the Retraction Watch user guide (e.g., “Falsification/Fabrication of Data”, “Investigation by Company/Institution”, “Plagiarism of Article”)
• RetractionDOI — linkable DOI of the retraction notice itself

When a DOI appears in both Crossref’s update-to[] and the RW CSV, the RW entry takes precedence because it carries richer reason metadata. Source attribution (“via Retraction Watch” or “via Crossref”) is shown per-flag in the result UI.

Reference: The Retraction Watch Database. Retraction Watch is operated by The Center for Scientific Integrity, a 501(c)(3) nonprofit, edited by Ivan Oransky and Adam Marcus.

DOAJ withdrawn-journals log

Directory of Open Access Journals · Misconduct-removal flag

DOAJ maintains a public record of journals removed from the directory for reasons including editorial misconduct, predatory practices, and ceased publication. DOAJ-withdrawn screening is not currently active in Sentry: DOAJ does not publish a reliable machine-readable withdrawn-journals feed (the historical change log is being retired), so rather than ship an unreliable check we have held it back. When a dependable source is available, Sentry will surface these as “DOAJ-withdrawn” with the reason category.

Reference: Directory of Open Access Journals (DOAJ).

Retraction Watch Hijacked Journal Checker

Tracker of titles being impersonated by predatory websites

Retraction Watch maintains a Hijacked Journal Checker (public Google Sheet) tracking journals being impersonated by predatory clone websites that mimic established venues. Sentry mirrors this list weekly into a clone-domain set, over a bundled floor that ships with the app so the check works even between syncs.

We match by clone URL/domain only — never by ISSN or journal name. This is deliberate, and it is the safety-critical design choice of this check: a hijacked clone steals the legitimate journal’s exact ISSN and title, so matching on either would falsely flag legitimately-cited papers in the real journal. The clone’s web domain is unique to the clone, so it is the only false-positive-free signal. As a safety belt we also subtract every legitimate-journal domain from the clone set. A reference is flagged only when its text cites a known clone domain; a paper that resolves cleanly via Crossref is never flagged.

When flagged, Sentry names the clone domain and notes that hijacked sites copy a real journal’s name and ISSN, so the reader should confirm the cited content is actually from the legitimate journal rather than the clone.

Reference: Retraction Watch Hijacked Journal Checker.

Severity precedence

When multiple checks return positives for the same reference, Sentry collapses to a single highest-severity verdict for the card UI:

1. Retracted — trumps everything; remove or replace the citation
2. Expression of Concern — publisher-level concern, paper not retracted
3. Hijacked Journal — reference cites a known clone domain; verify the citation source
4. Correction — corrected/erratum/addendum; verify any specific numerical claims
5. Clean — DOI resolves, no integrity flags
6. Unverifiable — no DOI in the entry, or DOI did not resolve via Crossref

Hijacked-journal outranks correction because it’s a venue-level integrity category: a correction in a normal journal is a footnote, but a reference that cites a hijacked-journal clone is one reviewers may flag regardless of the paper’s own merit.