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BibTeX Validator

Upload or paste a .bib file to check syntax, missing fields, dead DOIs, and verify your citations actually exist, including author and year correctness. Download a corrected .bib where CrossRef returns a confident match. Useful for catching AI-hallucinated references. Files are never stored.

Drag a .bib file here, or choose one. Max 2 MB.

Checks to run

Enabling DOI or database checks will send entry titles and authors to external services (doi.org, CrossRef, Semantic Scholar).

Files are never written to disk or logged.

How to validate a BibTeX file online

  1. Upload your .bib file (drag-and-drop or click), or switch to Paste text and drop the BibTeX directly. Up to 2 MB.
  2. Syntax and required-field checks run automatically. Enable DOI resolution and/or CrossRef / Semantic Scholar checks to verify your citations actually exist (and that authors and years match).
  3. Click Validate .bib. A color-coded table shows each entry. Click any row to see the original BibTeX, plus the corrected version when CrossRef returned a confident match. Use the filter chips to focus on warnings or errors.
  4. Download the annotated .bib (your file with status comments) or the corrected .bib (entries rewritten from CrossRef metadata where confidence is high).

If the table lists errors you do not recognize, the guide shows how to fix the errors the validator finds, with a before and after for each of the eight most common.

About this tool

This tool validates BibTeX files in layers: syntax + completeness (always), DOI resolution (opt-in), and existence checks against CrossRef and Semantic Scholar (opt-in). When you enable the database checks, it also compares authors and publication years and can produce a corrected .bib for high-confidence matches. It's particularly useful for catching AI-hallucinated citations that have plausible-looking metadata but don't correspond to real papers.

Can it detect AI-hallucinated citations?
Yes. Enable the CrossRef and/or Semantic Scholar checks. For each entry with a title, the tool queries the database and reports how closely the title and author list match a real paper, and whether the year is off. Low-confidence title matches (below 50%) and author mismatches on otherwise-confident matches are flagged as likely hallucinations. For the full workflow and how the detection methods compare, see the guide on catching AI-hallucinated citations.
Are my files stored?
No. Your .bib file is validated in an ephemeral container and discarded immediately. When you enable DOI or database checks, titles and authors are sent to those external services. This is disclosed before you run the check.
What does the annotated .bib contain?
Your original .bib file with a comment line above each entry showing its validation status: missing required fields, DOI result, title and author confidence scores, and any year mismatch. Paste it straight back into your editor.
What is the corrected .bib?
For each entry where CrossRef returned a high-confidence match (title similarity at least 85%), the corrected .bib replaces the entry's fields with authoritative metadata: title, author list, year, DOI, journal or booktitle, volume, issue, pages, and publisher. Entries without a confident match are passed through unchanged. Each rewritten entry is marked with a "CORRECTED from CrossRef" comment so you can audit the changes.
How does the author check work?
Names are normalized to canonical last-name tokens (folding "John Smith", "Smith, John", "J. Smith", and "Müller" → "muller" all to the same key) and compared as a set against the authoritative author list. The score is the Jaccard overlap, so partial matches still get partial credit.
What BibTeX entry types are supported?
article, book, inproceedings, proceedings, phdthesis, mastersthesis, techreport, misc, incollection, inbook, booklet, manual, conference, unpublished, and thesis.

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