Citation checker: catch fake DOIs before your professor does.

Every source gets checked in several ways: DOI format, a real lookup against the Crossref and PubMed registries, and a cross-check of the journal name. URLs are actually visited rather than judged on how plausible they look, which is what catches the invented ones. Results are confidence-scored so you know which to chase first.

Because they look completely real. Language models produce plausible authors, believable journal names and DOIs with the right shape, and none of it exists. Grading software increasingly catches this, and by then it reads as fabrication rather than a mistake.

APA, MLA, Chicago, IEEE, Vancouver, numbered lists, bullet lists and plain text. The parser copes with the messy in-between versions too, which is what most bibliographies actually look like.

Use Essay plus sources mode. It reads the essay, finds the inline citations, matches them against your reference list and verifies each one, so you also catch the reference you cited but never listed.

Peer-reviewed sources verify most confidently. Books and websites get partial verification, since we often can't confirm a specific edition or what a page said on the day you read it.

Hit Recheck first, because a DOI server having a bad minute can cause a false flag. If it keeps failing, something in the citation is usually off by a little: wrong year, wrong journal, a digit out in the DOI.

Turnitin asks whether you copied the text. We ask whether the sources exist at all. Those are different problems and in 2026 both of them matter.