FLEDGE has been renamed to Protected Audience API. To learn more about the name change, see the blog post

Some online advertising has been based on showing an ad to a potentially-interested person who has previously interacted with the advertiser or ad network. Historically this has worked by the advertiser recognizing a specific person as they browse across web sites, a core privacy concern with today's web.

The TURTLEDOVE effort is about offering a new API to address this use case while offering some key privacy advances:

• The browser, not the advertiser, holds the information about what the advertiser thinks a person is interested in.
• Advertisers can serve ads based on an interest, but cannot combine that interest with other information about the person — in particular, with who they are or what page they are visiting.
• Web sites the person visits, and the ad networks those sites use, cannot learn about their visitors' ad interests.

Chrome has been running a FLEDGE Origin Trial since milestone 101 (March 2022). For details of the current design, see the FLEDGE explainer or the in progress FLEDGE specification.

The FLEDGE design draws on many discussions and proposals published during 2020, most notably:

• The original TURTLEDOVE from Chrome.
• SPARROW from Criteo, which entered WICG incubation jointly with TURTLEDOVE.
• Outcome-based TURTLEDOVE and Product-level TURTLEDOVE from RTB House.
• Dovekey from Google Ads.
• PARRROT from Magnite.
• TERN from NextRoll.

Many additional contributions came from Issues opened in this repo, and from discussion in the W3C Web Advertising Business Group.