Categories: Do Not Track privacy

DNT: 1 = “Tell sites I do not want to be tracked”

Mozilla lands Do Not Track HTTP header into nightly builds today: 30 lines of code to support more privacy online.

My colleague, Sid Stamm, Mozilla’s privacy engineer announced this morning that we have uploaded working prototypes of our Do Not Track HTTP header in nightly builds (pre-beta versions of Firefox). Anyone interested in testing it out can download one of these versions and see how we are implementing the header.

In collaboration with the researchers at Stanford’s, we have modified the header to now state “DNT: 1” when a user turns on the option within the browser. This is shorter than the original proposal for “X-Do-Not-Track,” and this is what we will be bringing forward to the industry.

Testers will not notice any difference in browsing online until sites and advertisers start to respond to the header. For now, broadcasting DNT: 1 will be akin to displaying EFF’s Blue Ribbon campaign, for those of you who remember the popular online rights campaign from the 90s.

Currently, the feature shows up in the “Advanced” panel within Firefox Preferences. It pains me that it’s not under the “Privacy” panel, yet. This reflects our desire for speed in getting the feature into Firefox, as updating the “Privacy” UI and content will require additional engineering bandwidth. We’ll have more to say on this once we move the new feature into upcoming beta releases.

We were blown away by the overwhelmingly positive response to last week’s announcement of our HTTP header proposal. We are having daily interactions with a broad array of interested companies, advertisers, consumer advocates, developers, and researchers to flesh out the details of how to interpret the header. Everyone here at Mozilla remains committed to working with all stakeholders in determining whether this approach provides a more nuanced, persistent and simple way for users/sites/advertisers to recognize and respect choice and control online than other opt-out or blocking mechanisms.

Alex Fowler

(Image: Zazzle mock-up for a different kind of do-not-track “header” based on our implementation.)

One comment on “DNT: 1 = “Tell sites I do not want to be tracked””

  1. Ping from Do Not Track goes mobile: Mozilla demos preference at Mobile World Congress | Mozilla Privacy Blog on

    […] was the first major browser to provide its users with Do Not Track on desktop and mobile. Firefox for Android provides users […]