v144 · miscellaneous

Deprecate and remove: Private Aggregation API

The Private Aggregation API is a generic mechanism for measuring aggregate, cross-site data in a privacy preserving manner. It was originally designed for a future without third-party cookies.

concepts

  1. Private Aggregation Note

    Private Aggregation API (the aggregated-noise reporting backbone for Privacy Sandbox) is removed. Sites move to direct first-party reporting.

  2. Reporting Alternatives

    Probe for privateAggregation worklet APIs and surface the recommended replacements — first-party reporting plus server-side aggregation.

  3. Noise & Budget Simulator

    Sliders for true count, epsilon, and L1 budget — watch the Laplace noise eat your signal at low volumes. Visualises why the budget existed and where the API failed in practice.

  4. Histogram Explorer

    Build a histogram bucket interactively — pick key, value, and epsilon — then see Laplace noise transform the true value. Plots the noisy distribution on canvas with a live signal-to-noise ratio.

why it shipped

Chrome has announced[0] that the current approach to third-party cookies will be maintained. Given this, we expect adoption of the Private Aggregation API to decrease over time as cross-site measurement will remain possible in Chrome using third-party cookies. Further, other browser engines have not signaled interest in launching the API. Removing this (and certain other Privacy Sandbox APIs[1]) will help focus efforts on the proposed interoperable Attribution[2] standard.

references