Trust Center
LegiMatch is legal research and brief checking for U.S. attorneys. Before you rely on a tool for a filing, you should know how accurate it is, where its law comes from and what happens to your client's information. Here is all three, with the evidence.
Accuracy, measured and published
From our blind tests on real court decisions and U.S. Supreme Court briefs: 21 rounds, 1,635 documents, 43,046 citations and 10,741 planted mistakes so far. Full method and every round: how accurate is Brief Check and our similar-case test.
of planted case-citation mistakes caught - wrong year, page, name, court, volume, invented or swapped case, misquotation (latest two blind rounds, 1,397 of 1,417)
real citations wrongly called nonexistent in the same rounds
planted wrong pin pages caught
statute sections changed to another real section caught by the statute meaning check
of Case Match tests put the exact original decision in the top 10 (68 of 80 rewritten real decisions)
real quotations traced to the decision they came from, in under a second
Our commitments
Only real decisions
Every result is a court decision stored in our library, with a link to the opinion. The AI can explain a match; it can't introduce a case.
Tested in the open
We plant mistakes in real court documents nobody has used before and publish how many we catch - and how often we wrongly flag a correct citation.
Re-tested every week
The tests are re-run on new documents every week and after every change to the checker, and the numbers here are updated.
Honest about limits
When a citation can't be checked - a reporter or a decision we don't hold - the report says so instead of calling it fake.
Where the law comes from
Court decisions
The courts' own opinion text - U.S. Supreme Court, federal courts of appeals and district courts, and state courts - from public sources, with original page numbers. No publisher headnotes. Updated daily.
Citation index
A citation index of millions of U.S. decisions, used to confirm that a cited case exists and has that name and year even when we don't hold its full text.
Statutes
The official text of the U.S. Code and of state codes, loaded from each government's official source; more states are being added.
Later treatment
Warnings when later decisions in our library overrule, reverse or question a case. These come from the decisions themselves; they're not a full editorial citator.
Security and confidentiality
Encrypted, stored on U.S. servers and never used to train AI, with automatic PII redaction, auto-delete and two-factor sign-in. Details and subprocessors: Security & confidentiality.