Libwww is an early World Wide Web software library providing core functions for web browsers, implementing HTML, HTTP, and other technologies. Tim Berners-Lee, at the European Organization for Nuclear Research (CERN), released libwww (then also called the Common Library) in late 1992, comprising reusable code from the first browsers (WorldWideWeb and Line Mode Browser).
Libwww was relied upon by the then popular browser Mosaic. By 1997, interest in libwww declined, and the World Wide Web Consortium (W3C), which took over from CERN, reduced its commitment to the project. Later, the purpose of libwww was redefined to be "a testbed for protocol experiments"; in that role it was maintained for the benefit of the W3C's web standards-promoting browser Amaya. Active development of libwww stopped in 2000.