ZIM (file format)

ZIM archive format
Kiwix ZIM reader on an Android-powered tablet showing the article from Wikipedia for Schools in offline usage
Filename extension
.zim
Internet media typetext/plain, application/octet-stream
Magic number0x44D495A
Latest release
6.3
April 16, 2025; 18 months ago (2025-04-16)
Type of formatData compression
CompressionZstandard, LZMA2
Container forWikimedia and other web content for offline use
Open format?Yes
Free format?Yes
Websitehttps://wiki.openzim.org/wiki/OpenZIM

The ZIM file format is an open file format that stores website content for offline usage. The format is defined by the openZIM project, which also supports an open-source ZIM reader called Kiwix. The format is primarily used to store the contents of Wikipedia and other Wikimedia projects, including articles, full-text search indices and auxiliary files.

ZIM is an abbreviation for 'Zeno improved', as it replaced the earlier Zeno file format. Since 2021, the library defaults to Zstandard file compression, and also supports LZMA2 compression, as implemented by the XZ Utils library. Most notably, the compression ratio can be up to 3∶1 with almost all of the space savings taking place within the clusters.

See also

References

  1. ↑ openzim/zimit, openZIM, 2024-09-10, retrieved 2024-09-11
  2. ↑ "openZIM project wiki". Retrieved 4 April 2012.
  3. ↑ Truong, Kevin (2020-07-10). "You Can Download the Entirety of English Wikipedia to Browse Offline". Vice. Retrieved 2023-07-27.
  4. ↑ "Zeno File Format". openZIM.org. Retrieved 10 April 2012.
  5. ↑ ".ZIM File". FILExt. Retrieved 10 April 2012.
  6. ↑ "Release 7.0.0". GitHub. Retrieved 9 August 2024.
  7. ↑ "ZIM Format Block Diagram" (PDF).