FLEDGE Legacy
Data & TrackingAlso: FLEDGE · First Locally-Executed Decision over Groups Experiment · Protected Audience API predecessor
Quick definition
FLEDGE (First Locally-Executed Decision over Groups Experiment) was Google's early Chrome proposal for running remarketing auctions on-device instead of through third-party cookies. It has since been renamed the Protected Audience API. The term survives in old documentation, vendor decks and outdated audits.
What it actually means
FLEDGE was Google's working name for a piece of the Privacy Sandbox built to replace what third-party cookies used to do for remarketing. The idea was simple in outline and complicated in practice. Instead of a cookie following a user around the web so an advertiser could retarget them, the browser itself would hold a private list of interest groups and run a small auction locally, on the device, without handing raw identity data back to ad tech.
Google renamed FLEDGE to the Protected Audience API partway through development. The renaming wasn't cosmetic. Scope, auction mechanics and reporting all shifted as Chrome moved from proposal to shipped feature. Anyone still citing FLEDGE by name is citing an earlier draft of the system, not what's actually running in Chrome today.
This matters for marketers because retargeting, attribution and audience segmentation are all downstream of whichever cookie-replacement mechanism ends up standard. Confusing FLEDGE with its successor leads to stale expectations about what data you can and can't access, and what your programmatic partners are actually doing under the hood.
FLEDGE is a name, not a feature. If a vendor still leads with it, they haven't updated their pitch since the cookie deprecation timeline moved.
How it shows up
FLEDGE shows up almost entirely in legacy content: old Chromium developer blog posts, cached vendor whitepapers, and internal documentation nobody updated after the rename. It occasionally surfaces in RFPs and audits where a consultant copied language from an older source. It doesn't show up in current campaign settings, current Chrome flags or current IAB guidance, all of which have moved to Protected Audience API terminology.
The Australian context
Australian publishers and agencies leaning on programmatic revenue have been watching the Privacy Sandbox timeline closely because Google's cookie deprecation plans directly affect how retargeting and frequency capping work locally. The relevant regulatory backdrop here is the Privacy Act reforms and the Office of the Australian Information Commissioner (OAIC), which are pushing local advertisers toward first-party data and consent-based targeting regardless of what Chrome ships. FLEDGE itself was never Australia-specific, but its replacement's rollout timeline affects how quickly local martech stacks need to migrate off third-party cookie dependent segmentation.
Where people get this wrong
Related terms
Common questions
Is FLEDGE still used in Chrome?
No. FLEDGE was the working name for a Privacy Sandbox feature that Google renamed to the Protected Audience API as the specification matured. Any current implementation runs under the new name, not the old one.
What's the difference between FLEDGE and the Protected Audience API?
They're largely the same underlying system at different points in development. The rename came with changes to auction mechanics and reporting, so treat Protected Audience API documentation as the accurate current source and FLEDGE material as historical.
Does FLEDGE replace third-party cookies entirely?
No. It addresses remarketing and interest-group auctions specifically, run on-device rather than through a tracking cookie. Other cookie-dependent functions like cross-site attribution needed separate Privacy Sandbox proposals to address.
Why do I still see FLEDGE mentioned in marketing materials?
Usually because the material is outdated. Vendors and agencies sometimes reuse older technical explainers without updating terminology after Google's naming changes. Treat any FLEDGE reference as a flag to ask what's actually currently implemented.
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New Rebellion is a marketing intelligence consultancy. We build tools, score Australian businesses on how their marketing actually performs, and publish Debrief every day. This dictionary is part of how we work in the open.
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