How to verify a case citation is real
A 5-minute deterministic check, updated July 18, 2026.
Verifying a case citation is a three-step check: (1) does the case exist in a real reporter or docket, (2) does the quoted language actually appear in the opinion, and (3) does the opinion support the proposition it’s cited for. Steps 1 and 2 are deterministic — a citation either exists in CourtListener or it does not, and a quoted string either appears in the opinion text or it does not. Step 3 requires judgment.
Step 1 — Confirm the case exists
Take the citation exactly as written and search for it in an authoritative primary-source database. For U.S. federal decisions the canonical free sources are the Free Law Project’s CourtListener (courtlistener.com) and, for filings and dockets, PACER. For state decisions, the reporter series and the official state court website are authoritative. If the citation is in the form “123 F.3d 456 (7th Cir. 2020),” open the F.3d reporter volume 123 at page 456 in CourtListener. The case either exists under that volume-page combination or it does not.
Two failure modes to watch for. First, do not ask a chatbot “does this case exist?” — in Mata v. Avianca (S.D.N.Y. June 22, 2023), ChatGPT confidently insisted six fabricated cases were real when asked, and even produced fake excerpts of the nonexistent opinions to prove it. Second, do not accept a Westlaw or Lexis identifier at face value if the case is unfamiliar; unpublished-order citations (“2019 WL 13202785” and similar) are a favorite target of AI fabrication precisely because they carry the surface texture of a real citation without the underlying published-reporter check.
Step 2 — Confirm the quote
If the citation is attached to a quoted string, open the opinion in the primary source and search for the quoted text. If the quote does not appear verbatim in the opinion, the citation is misrepresenting the source. AI misquotation is nearly as common as AI fabrication in the sanctions record: the Charlotin dataset categorizes hundreds of rulings where the case existed but the quoted language did not appear in the opinion at all. Del Biaggio v. Bansen (July 2026) and Michael L. Ruiz v. Magellan Financial & Insurance Services (July 2026) are two recent examples.
Step 3 — Confirm the proposition
The hardest and most subjective step: does the opinion actually support the proposition the brief is citing it for? A real case can be cited for a rule it never announced, or its holding can be materially overstated. This step requires reading the opinion — no shortcut, no verifier can replace lawyer judgment here. Citation Safe’s proposition-support layer flags obvious mismatches with a confidence score and always reports as evidence for your judgment, never as a substitute for it.
The free tool
Citation Safe’s free reverse-check widget runs Step 1 and Step 2 deterministically against CourtListener and the reporter series — no LLM in the existence check, no LLM in the quote-match check. Paste a citation and get a verdict (VERIFIED, UNCONFIRMED, or NOT FOUND) in about two seconds.
Reverse citation check
Paste a brief. We'll flag anything fabricated.
Free: we'll show you which citations couldn't be verified. $19 unlocks the full annotated report -- no signup.
Layer 1–2 check (existence + quote match) against primary sources. Not legal advice.
Related resources
- List of AI-hallucinated cases — over 200 fabricated citations documented in real court rulings.
- Fake ChatGPT case citations — the Mata v. Avianca corpus and the pattern that started them.
- AI sanctions tracker — every court sanction imposed for AI-hallucinated citations.
- Full verification tool — batch upload, brief mode, proposition-support layer.
Written by the Citation Safe Research Desk · Reviewed by Andy Gaber, Founder