The WHATWG was founded by individuals from Apple Inc., the Mozilla Foundation and Opera Software, leading Web browser vendors in 2004.

[2][3] WHATWG is responsible for maintaining multiple web-related technical standards, including the specifications for the HyperText Markup Language (HTML) and the Document Object Model (DOM).

[4][5] The central organizational membership and control of WHATWG – its "Steering Group" – consists of Apple, Mozilla, Google, and Microsoft.

[7] The WHATWG mailing list was announced on 4 June 2004,[8] two days after the initiatives of a joint Opera–Mozilla position paper[9] had been voted down by the W3C members at the W3C Workshop on Web Applications and Compound Documents.

[12] An Internet Explorer platform architect from Microsoft was invited but did not join, citing the lack of a patent policy to ensure all specifications can be implemented on a royalty-free basis.