A C library for WWW software written and maintained at CERN, later at the W3 consortium.
The library was originally (in 1992) ported from the Objective C code native to the Web's first operational platform, NeXTStep.
Its thoroughly object oriented design, lack of documentation, and lack of an active user community, made it hard to use for WWW programmers. It was more tempting for them to start from scratch.
The library is very extensible; it has always supported multiple network protocols (HTTP, FTP, Gopher, NNTP, local file transfers, etc.), and multiple document formats, including a built-in HTML handling library.
There is a common part, a client-specific part, and a server-specific part. CERN httpd and the browsers developed at CERN (now at W3) such as the line-mode browser, Arena and Amaya are fully based on libwww; some other web software, such as the Lynx and NCSA Mosaic browsers, use some of its code, but in a copied form, without any of the improvements made in recent years, when development continued, led by Henrik Frystyk-Nielsen.
A counterpart in Perl, called libwww-perl, was created by Roy Fielding in 1994; it bears no relationship to the original libwww except the name and purpose.