Do Not Track

Do Not Track (DNT) is a deprecated non-standard^[1] HTTP header field designed to allow internet users to opt out of tracking by websites—which includes the collection of data regarding a user's activity across multiple distinct contexts, and the retention, use, or sharing of data derived from that activity outside the context in which it occurred.^[2]

The Do Not Track header was originally proposed in 2009^[3] and was adopted by most major browsers within a few years. However, the header failed to find widespread respect among the publishers,^[4] due to the lack of legislation requiring companies to legally respect the DNT header and confusion about the header meaning.^[5] The DNT header was abandoned by standards bodies such as the W3C.^[4] As of 2025, some browsers had removed the header, including Apple Safari and Mozilla Firefox.^[6]

Following the failure of the DNT initiative, a coalition of US-based internet companies announced the creation of the Global Privacy Control header which is intended to have explicit legal force under privacy legislation.

The DNT header accepts three values: 1 in case the user does not want to be tracked (opt-out), 00 in case the user consents to be tracked (opt-in), or null (no header sent) if the user has not expressed a preference. The default behavior required by the document draft is not to send the header unless the user enables the setting via their browser or their choice is implied by the use of that specific browser.^[7]