Reference & citation checker
Paste your reference list and check whether every citation is real. Folio looks up each reference in Crossref and OpenAlex, with arXiv as a second opinion, flags the ones it can't find (often a sign of an AI-hallucinated source) and the papers that were retracted, and gives back the record's own year, DOI and APA 7 citation so you can fix each entry. 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. Uncertain means a record exists but its year, authors or DOI differ from the citation. Not found means no confident match. It is 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 Retracted means the paper is real but has been withdrawn from the literature and should not be cited as valid evidence.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 in Crossref and OpenAlex, the authoritative scholarly databases. If a reference has a DOI, it is resolved directly; otherwise the title is matched, and the authors and year must agree too. When those indexes miss a paper or carry it with the wrong year, arXiv is asked for a second opinion before anything is flagged. 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 fix my references?
It shows what the record says so you can fix each entry yourself: the year when yours differs, the DOI when yours is missing or points to a different paper, and the reference formatted in APA 7 from the record itself, ready to copy. It never rewrites your list. Verified references can be saved to a Folio library in one click.
What does “couldn’t check” mean?
That one of the indexes did not answer in time, or that the entry is a book or web page outside what they cover. It is never a verdict about the reference. Check again in a minute, or confirm a book in a library catalog.
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.
Why was a real reference marked “not found”?
The checker is conservative: it only marks a reference “verified” when it finds a confident match. Very recent papers, books, gray 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.
Can it check citations generated by ChatGPT or other AI?
Yes. That’s exactly what it’s for. AI writing tools often fabricate citations that look real: plausible authors, titles, and even DOIs for papers that don’t exist. Paste the AI-generated reference list here and the citation checker flags every entry it can’t verify against Crossref, OpenAlex or arXiv, including real DOIs attached to papers that were never written, so you catch hallucinated sources before you submit.
Is this a reference checker or a citation checker?
Both. They’re the same job under two names. Every entry in a reference list is a citation, so whether you’re checking your references or checking your citations, this tool verifies each one against the scholarly record and flags anything it can’t find or that has been retracted.