Paste your text and your reference list. The checker lists citations that have no entry, entries you never cite, years or names that differ between the two, and duplicate entries. It runs in your browser: your text stays on your device, and the checker changes nothing in it.
The check runs in this page, in your browser. The page sends your text and your list nowhere and stores nothing; close the tab and they are gone. Only if you click Check DOIs at Crossref does your browser ask the public Crossref database about each DOI in your list. Of your own data, only the DOI goes along: no text, no names, no account and no email address.
A reference list drifts during a thesis. You drop a source from a chapter but not from the list, you cite a preprint and later add the published version, or a name gets a letter wrong in one of the two places. The checker reads every author-date citation in your text and sets it against your reference list. It reports four things:
The text and the list below are made up. The names, journals and titles do not exist. The button Try the example above loads them into the checker.
The text: Night shifts are linked to poor sleep among nurses (Okafor, 2020). Okafor and Lindqvist (2019) describe how rotating schedules slow recovery, and a later study reports the same pattern in intensive care (Moreau et al., 2021). Brennan (2018) reaches a different conclusion for day staff. Short breaks reduce errors in two studies (Halvorsen, 2022; Okafor, 2021). Mueller (2015) adds a cost perspective, and Ferreira (2019) looks at older nurses.
The reference list has eight entries: Brennan (2017), Halvorsen (2022), Moreau, Lee and Park (2021), Müller (2015), Okafor (2020), Okafor and Lindqvist (2019), Sato (2016), and Halvorsen (2022) a second time.
The checker reports one citation without an entry (Ferreira, 2019), one entry that is never cited (Sato, 2016), three differences marked Check (Brennan 2018 against 2017, Okafor 2021 against the Okafor entries from 2020 and 2019, and Mueller against Müller) and one duplicate (the two Halvorsen entries). The citation of Moreau et al. matches the entry with three authors, and Okafor and Lindqvist (2019) matches the entry with both names.
None of these findings says what the right version is. Brennan may have published in 2017, or your text may be right and the list wrong. Mueller and Müller may be the same person spelled two ways, or two different authors. You decide, with the source in front of you.
The checker recognizes citations in parentheses, such as (Okafor, 2020), (Okafor & Lindqvist, 2019) or (Halvorsen, 2022; Okafor, 2021), and narrative citations, such as Okafor (2020) or Moreau et al. (2021, p. 4). It reads et al., two authors joined by and or &, letters after the year (2021a, 2021b), n.d. for sources without a date, page numbers after the year, and prefixes such as see or e.g. In a secondary citation such as (Jones, 1990, as cited in Okafor, 2020), it looks only for Okafor, 2020, the source you read.
Capitals and particles do not matter: DUPONT, Dupont and dupont count as the same name, and so do Van der Berg and Berg, P. van der. When two spellings differ in an accent or in one or two letters, the checker still pairs them, but it does not decide for you: it lists the pair under Check.
The checker does not judge your citation style. It does not look at commas, italics, the order of the list, or whether you use and or &. It only asks whether your text and your list agree.
If entries in your list have a DOI, you can ask the public Crossref database about them with one click. Your browser then sends each DOI, and only the DOI, to Crossref. The checker compares the title, the year and the first author in the Crossref record with your entry and shows any difference under Check.
A difference is not always an error in your list. Many articles appear online a year before the print issue, so the years can differ by one. A title may have a subtitle in one place and not in the other.
Not found at Crossref does not mean the source is made up. Crossref is one of several DOI registration agencies: datasets, some books and many sources outside journals are registered elsewhere. Open the DOI link in your browser to see where it leads.
Esmond evaluates every assignment before you submit. It never writes it.
The citation checker compares names and years. Esmond's full review reads your whole thesis and looks at content, argument and sources: whether each claim in your text is backed by a source, and where your reasoning goes further than your evidence.
No. The check runs in your browser. The page sends your text and your list nowhere and stores nothing. Only if you click Check DOIs at Crossref does your browser send the DOIs from your list to Crossref, one by one, without any other text.
Author-date styles: APA, Harvard, Chicago author-date and similar styles where a citation names the author and the year. Numbered and footnote styles are not supported.
No. The checker does not judge commas, italics, capitals or the order of your list. Which style you follow is between you, your department and your advisor. The checker only compares your text with your list.
That Crossref has no record for that DOI. Not found at Crossref does not mean the source is made up: the DOI may be registered with another agency, or it may contain a typo. Open the DOI link to see where it leads.
No. It needs no account, sends you no email and has no limit on how often you use it.
Read on November 7, 2026.
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