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CiteKit
Open Reference Library

Citation Link Checker

The Citation Link Checker checks whether Source identifiers and links can still be resolved. Paste DOIs, ISBNs, YouTube URLs or IDs, or general URLs, and CiteKit runs the appropriate resolution check for each one.

Use it before publication, during an update, or when revisiting older References to find links and identifiers that may need attention.

The Citation Link Checker is designed to identify resolution and accessibility problems, including:

  • Unreachable URLs — links that no longer return an accessible page.
  • Identifiers that do not resolve through the service being checked — for example, a DOI or ISBN lookup that returns no matching record.
  • Redirects — URLs that now resolve somewhere other than the address you entered.
  • Malformed inputs — identifiers or URLs that cannot be parsed or checked as entered.
  • Temporary check failures — cases where the Source may be valid but the lookup cannot be completed because of a network or external-service problem.

A successful check means the identifier or link resolved through the method CiteKit used. It does not prove that the Source is accurate, trustworthy, relevant, or correctly cited.

The basic workflow

  1. Paste the Source identifiers or links you want to check, one per line. You can mix supported types in the same check.
  2. Run the check. CiteKit detects the input type and uses the appropriate resolution method.
  3. Review the result for each Source. Pay particular attention to items that cannot be resolved, redirect unexpectedly, or return a technical error.
  4. Correct the underlying Reference when needed. If a URL, DOI, ISBN, or other identifier has changed or was entered incorrectly, update the Source Metadata stored on the Reference.
  5. Run the check again after making corrections.

How different Source identifiers are checked

The checker uses different methods depending on the type of input:

  • DOIs — checked through a DOI metadata lookup. If the lookup does not return a record, review the DOI for transcription errors or verify it against the publisher or another DOI registry.
  • ISBNs — checked through a book metadata lookup. A failed lookup means CiteKit could not resolve that ISBN through the service used for the check; it does not by itself prove the ISBN is invalid.
  • YouTube URLs and video IDs — checked to determine whether the referenced video can still be resolved through YouTube’s available metadata endpoint.
  • General URLs — checked through an HTTP request to determine whether the address responds and whether it redirects.

For general URLs, a successful response only tells you that the URL is reachable. You should still confirm that the page is the Source you intended to cite, particularly when a domain or publication has reorganized its content.

Understanding the results

The exact result shown depends on the Source type and the response returned by the lookup, but the important distinction is between a successful resolution, a Source that could not be found or reached, a redirect, and a technical error.

  • Accessible or resolved — the identifier or URL responded successfully through the check being performed.
  • Not found or unreachable — CiteKit could not resolve the identifier or reach the URL through the expected method.
  • Redirected — the original URL resolves to another location. Review the destination before deciding whether the Reference should be updated.
  • Error — the check could not be completed. This can reflect a temporary network problem, an external-service failure, access restrictions, or malformed input.

A failed or errored check should be treated as a prompt for review, not as an automatic judgment about the Source itself.

Checking References before publication

If you already have Sources saved in CiteKit, the Link Checker fits naturally into the Reference workflow:

Source → Reference → Link check → Citation / Bibliography / publication

The Reference is the reusable CiteKit record representing the Source. If a check reveals that an identifier or URL needs to change, update the Reference’s Source Metadata so future Citations, Bibliography Entries, and other outputs use the corrected information.

What to do when a Source does not resolve

The next step depends on what failed:

  • URL does not resolve — check for a newer publisher URL, an official replacement page, or an archived copy where appropriate.
  • DOI does not resolve — compare the DOI against the publisher page or another trusted bibliographic record and correct any transcription error.
  • ISBN does not resolve — verify the edition and ISBN against the publisher, library catalog, or another reliable book record.
  • YouTube video is unavailable — determine whether the video was removed, made private, or replaced, and decide whether another Source is needed.
  • The check returns an error — retry later or verify the Source manually before changing the Reference.

Using the checker with AI-assisted research

When Sources come from an AI-assisted research or drafting workflow, the Citation Link Checker can help confirm that supplied identifiers and links actually resolve. That is useful because generated Source details can contain transcription errors or point to material that cannot be located.

Resolution is only the first verification step. A Source that resolves still needs to be checked for authorship, title, publication details, relevance, and whether it actually supports the claim being made.

  • It does not prove that a Source is true or authoritative. It checks resolution and accessibility.
  • It does not prove that a Source supports a particular claim. That requires reviewing the Source itself.
  • It does not guarantee that a failed identifier is fabricated. Metadata services can be incomplete or temporarily unavailable.
  • It does not replace Source Metadata review. Names, dates, titles, publication information, and identifiers should still be checked when accuracy matters.

Using the checker with the Reference Library

The Reference Library stores reusable References. Link checking is one maintenance step you can perform before those References are used again in Citations, Bibliographies, Reference Sets, or published source lists.

This keeps link health separate from the Reference itself:

Reference Library
↓ contains
References
↓ can be checked for
identifier and link resolution

A Reference can remain useful even when one URL changes, as long as its Source Metadata is corrected to point to the appropriate current or archived Source location.

What’s next