Format

CDX Internet Archive Index

Summary

Name: CDX Internet Archive Index
Identifiers: PUID: fmt/869
Format type: Text (Structured)
Description: A CDX file consists of individual lines of text, each of which summarizes a single web document. The first line in the file is a legend for interpreting the data, and the following lines contain the data for referencing the corresponding pages within the host. The CDX signatures use a field delimiter character which is assumed to be a space character, however please contact the PRONOM team should you encounter CDX index files where the delimiter is different.
File extensions: cdx
Source: Digital Preservation Department / The National Archives

Note: BOF: <field delimiter (usually space)>CDX<field delimiter (usually space)>, followed by CDX options as described here: https://archive.org/web/researcher/cdx_file_format.php For signature strength we currently assume the field delimiter will be a space character (hex 0x20) rather than a wildcard, with scope to add further delimiters as they are encountered.

Note: BOF: 'CDX' <field delimiter (usually space)>, followed by CDX options as described here: https://archive.org/web/researcher/cdx_file_format.php. This format could potentially be strengthened if necessary with the inclusion of one or more of the CDX options, which are to date an alphabetic character (upper or lower case, a-z, A-Z with a few exceptions) or the hash value