PRONOM is an online registry of technical information about file formats, maintained by The National Archives (UK). The PRONOM database contains information about the properties of over 600 file formats, and is used by repository managers to understand, document and manage file formats stored in repositories. Information in the database includes extensions associated with file types, software required to render files, version histories of file types, signature types and compression information.
In addition to searching the registry via the web interface, PRONOM provides two important services related to file type identification and metadata extraction. The DROID tool, provides both a command line and GUI interface to the PRONOM registry allowing for easy documentation of file types. The PRONOM Unique Indentifier (PUID) tool allows unambiguous reference to data in the PRONOM database.