GNU libextractor is a library used to extract meta-data from files. The goal is to provide developers of file-sharing networks or WWW-indexing bots with a universal library to obtain simple keywords to match against queries.

Currently, GNU libextractor supports the following formats: HTML, PS, OLE2 (DOC, XLS, PPT), OpenOffice (sxw), StarOffice (sdw), DVI, MAN, FLAC, MP3 (ID3v1 and ID3v2), NSF (NES Sound Format), SID, OGG, WAV, EXIV2, JPEG, GIF, PNG, TIFF, DEB, RPM, TAR, ZIP, FLV, REAL, RIFF (AVI), MPEG, QT and ASF. Also, various additional MIME types are detected.