Reference checker
Paste a reference list and check whether each citation is real. Folio verifies every reference against CrossRef and OpenAlex, flags the ones it can't find — often a sign of an AI-hallucinated source — and warns you about retracted papers. Free, no sign-up.
Never cite a fake source again
Folio verifies every citation as you write — grounded only in real sources you add — and records a provable writing history. Integrity by default.
Why check your references?
AI writing tools routinely invent citations — plausible-looking authors, titles, journals, and even DOIs for papers that do not exist. Reviewers and instructors increasingly check, and a single fabricated or retracted reference can sink a submission. This tool looks up each reference in the authoritative scholarly databases so you can catch problems before anyone else does.
A verified result means the reference matched a real record. Not found means no confident match — worth a second look. Retracted means the paper is real but has been withdrawn from the literature and should not be cited as valid evidence.
Frequently asked
Is this reference checker free?
Yes — completely free, with no sign-up. Paste your reference list and check it. Your references are used only to look up matches and are not stored.
How does it detect fake or AI-hallucinated citations?
It looks up each reference against CrossRef and OpenAlex — the authoritative scholarly databases. If a reference has a DOI, it is resolved directly; otherwise the title is matched. References with no match are flagged: they may be mis-formatted, very new, or fabricated (a common failure mode of AI writing tools).
Does it check for retracted papers?
Yes. When a reference resolves to a real record, Folio also checks its retraction status and warns you if the paper has been retracted or carries an expression of concern — so you don’t cite discredited work.
A real reference was marked “not found” — why?
The checker is conservative: it only marks a reference “verified” when it finds a confident match. Very recent papers, books, grey literature, non-English titles, or heavily abbreviated references may not match even though they are real. Treat “not found” as “worth double-checking”, not proof of a fake.
How many references can I check at once?
Up to 25 per run. For a long bibliography, check it in batches. Everything runs server-side against free scholarly APIs — no account needed.