DOI checker: does the record exist, and does the title match?
One DOI, or a DOI plus the title you cited. Resolves against Crossref and DataCite. Dead DOIs, title mismatches, and retractions show up in seconds. This is existence, not formatting, and not a claim verdict.
Which job do you need?
I want APA or Harvard generated from the DOI
That is a generator. Scribbr or citation.doi.org are built for that. Acurio does not format citations.
I want to know this DOI exists and matches the title
That is this field. One DOI, optionally a title.
I want to know the source supports the sentence in my thesis
That is the analysis: thesis plus uploaded sources, not this mini-check.
What the DOI checker does
AI lists often pair a real DOI with a different title. The checker resolves the DOI and puts the registry title next to the text you supplied.
A dead DOI (no Crossref or DataCite record) is an existence problem. A live DOI with a retraction flag is too. Same core as Quick Check, here for one identifier.
For a whole reference list: Quick Check. For whether the source supports your claim: an analysis with uploads.
Frequently asked questions
What does the DOI checker verify?
Whether the DOI resolves in Crossref or DataCite, which metadata sits there, whether a supplied title matches, and whether the record is marked as a retraction.
Is it free?
Yes. One DOI, no account. A full list in Quick Check is also free. Claim-by-claim analysis of a thesis needs an account and credits.
Does this check APA or Harvard?
No. Formatting is a different job. This is identity: does the record exist, and is it the work you meant.