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NDL Web Archiving Project (WARP)

Free#5 of 22 in Web Archiving Software

NDL Web Archiving Project (WARP): A free national web archive for searching preserved websites, not submitting arbitrary URLs. Ranked #5 of 22 in Web Archiving Software by our editors (7.9/10); pricing: Free; best for researchers searching Japan’s national web archive.

7.9/10Editor score
NDL Web Archiving Project (WARP)7.9 Visit WARP

At a glance

  • Editor score
    7.9 / 10
  • Pricing
    Free
  • Best for
    Researchers searching Japan’s national web archive
  • Paid from
    Free
  • Snapshot capture
    Yes
  • Founded
    2002
  • Facts checked
    3 Oct 2026
  • Where it wins

    • Search archived page content with detailed filters for dates, publishers, and formats.
    • Browse archived versions and view capture dates and website metadata.
    • Access archive resources through Memento TimeMap and TimeGate endpoints.
  • Where it doesn't

    • Does not let users submit arbitrary URLs for capture.
    • Access to some archived material is limited to NDL premises.
    • Some formats, dynamic pages, and very large content may not be archived.

Our verdict on NDL Web Archiving Project (WARP)

WARP is the National Diet Library of Japan’s web archive, collecting and preserving websites such as public institutions’ sites and selected sites archived with publishers’ permission. It is suited to researchers and other visitors looking for preserved Japanese web material, rather than teams that need to capture arbitrary URLs on demand. The service is free and available through the web, with API access for archive resources. Its collection is managed by the NDL, not controlled by individual users.

Search covers full-text archived page content, with refiners for crawl date, domain or URL, title, publisher, content type, and organization type. Visitors can search website records, browse archived versions, and see website archive dates and metadata on detail pages. Supported material includes HTML, PDF, Microsoft Word, RTF, Excel, CSV, TSV, PowerPoint, text, and EPUB. Captures include an archive banner with capture information. Memento TimeMap and TimeGate endpoints offer a way to access archived resources programmatically; browser access is supported in current Chrome, Firefox, and Edge.

WARP’s main constraint is its collection and access model: the NDL operates recurring crawler schedules, and collection eligibility depends on law or publisher permission. Some material is available online, while other items can only be accessed at NDL premises. Some formats, dynamic content, or very large pages may not be captured. That makes WARP a fit for people researching material already in Japan’s national archive, especially when detailed search and archived versions matter. Organizations that require user-directed captures, control over crawl schedules, or guaranteed access to every archived item should consider a different kind of archiving service.

Your product? Our editors can test NDL Web Archiving Project (WARP) in depth and publish a review, labelled as paid · from $149/mo →

NDL Web Archiving Project (WARP) pricing

Plans FreeFree Free to use — no paid tier required for the core job.
See plans on warp.ndl.go.jp

NDL Web Archiving Project (WARP) fact sheet

Free planNot verified
Paid fromFree
Snapshot captureYes
Archive searchYes
Capture methodsAutomated web crawler operated by NDL; not a user-submitted URL capture tool
Preservation controlsNDL-managed recurring crawl schedules; access may be online or limited to NDL premises; collection eligibility depends on law or publisher permission
Supported contentHTML, PDF, Microsoft Word, RTF, Excel, CSV, TSV, PowerPoint, text, EPUB; some formats and dynamic or very large content may not be archived
Browser or API accessMemento TimeMap and TimeGate API endpoints; browser access using current Chrome, Firefox, or Edge
DeploymentCloud
PlatformsWeb
SupportDocs
Built forEnterprise (editorial estimate)
Integrations2 integrations: Memento TimeMap API, Memento TimeGate API See all →
PricingFree
Websitewarp.ndl.go.jp
Facts checked3 Oct 2026

NDL Web Archiving Project (WARP) integrations

NDL Web Archiving Project (WARP) lists 2 integrations on its own site.

  • Memento TimeMap API
  • Memento TimeGate API

See all NDL Web Archiving Project (WARP) integrations →

Alternatives to NDL Web Archiving Project (WARP)

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NDL Web Archiving Project (WARP) vs the competition

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Featured on iTechGuides

Featured on iTechGuides — NDL Web Archiving Project (WARP) 7.9/10

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Reviewed by iTechGuides Editors · Editorial team · Updated Oct 2026

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