Catch hallucinations before the court does.

HallucinX checks every case citation in your brief against a copy of CourtListener's public case-law data (Free Law Project), refreshed quarterly and dated on every report. Deterministic. Local-first. Explainable in court.

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How it works

01

Open a brief

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02

Check every citation

Citations are extracted from your brief in your browser. Only the citations — not the document text — are sent to our server, which checks each one against its own copy of CourtListener's public data. Deterministic string matching. No AI in the verification path.

03

File with confidence

Download a color-coded report. Every citation is verified, flagged, or marked for manual review, with a clear reason for every status. File it alongside your brief as your audit trail.

See it catch the fabricated citations from the Mata v. Avianca brief.

In 2023, two attorneys were sanctioned after filing a brief in Mata v. Avianca that cited six cases that did not exist. ChatGPT had hallucinated them; the lawyers did not verify. HallucinX catches all six — with an explanation a judge would accept for each.

Annotated excerpt: Mata v. Avianca — fabricated and verified citations side by sidePage 6 of the Peter LoDuca affirmation filed in Mata v. Avianca Airlines (22-cv-01461, S.D.N.Y.). HallucinX has flagged the fabricated Varghese v. China Southern Airlines citation and its invented block quote, confirmed 11 U.S.C. § 362(a) and Kaiser Steel Corp. v. W.S. Ranch Co. as real and correctly cited, and flagged the fabricated Zicherman v. Korean Air Lines citation.Case 1:22-cv-01461-PKC · Document 21 · Filed 03/01/23 · Page 6 of 10II. The Statute of Limitations is tolled by the bankruptcy of the defendantunder the Montreal Convention16The United States Court of Appeals for the Eleventh Circuit specifically17addresses the effect of a bankruptcy stay under the Montreal Convention in18the case of Varghese v. China Southern Airlines Co., Ltd., 925 F.3d 133919(11th Cir. 2019), stating “Appellants argue that the district court erred20in dismissing their claims as untimely. They assert that the limitations21period under the Montreal Convention was tolled during the pendency of the22Bankruptcy Court proceedings. We agree. The Bankruptcy Code provides that23the filing of a bankruptcy petition operates as a stay of proceedings against24the debtor that were or could have been commenced before the bankruptcy25case was filed. 11 U.S.C. § 362(a). The tolling effect of the automatic stay26on a statute of limitations is generally a matter of federal law. See Kaiser27Steel Corp. v. W.S. Ranch Co., 391 U.S. 593, 598, 88 S. Ct. 1753, 20 L.Ed.2d28835 (1968). We have previously held that the automatic stay provisions of29the Bankruptcy Code may toll the statute of limitations under the Warsaw30Convention, which is the precursor to the Montreal Convention. See Zicherman31v. Korean Air Lines Co., Ltd., 516 F.3d 1237, 1254 (11th Cir. 2008). We see32no reason why the same rule should not apply under the Montreal Convention.”Alert — fabricatedNo case by that name orcitation exists in anyreporter. Hallucinated.Alert — fabricatedBlock quote entirelyinvented. No such passageexists in any opinion.✓ VerifiedReal statute. BankruptcyCode automatic-stayprovision, correctly cited.✓ Verified391 U.S. 593 (1968) — areal Supreme Court case,correctly cited.Alert — fabricatedZicherman v. Korean AirLines does not exist at516 F.3d 1237. Hallucinated.Mata v. Avianca Airlines — 22-cv-01461 (S.D.N.Y.) — Affirmation of Peter LoDuca, March 1 2023 — annotations by HallucinX
Page 6 of the LoDuca affirmation. The italicized Varghese and Zicherman case names and the indented quotation were fabricated by ChatGPT and filed without verification. 11 U.S.C. § 362(a) and Kaiser Steel Corp. v. W.S. Ranch Co. are real and correctly cited.