v151 · performance · timing

Cross-origin Redirect Timing Opt-in

Servers can now opt in to have their cross-origin redirects measured by the destination page via the Resource Timing API. Previously, cross-origin redirect timing was hidden for privacy; now a Timing-Allow-Origin header on the redirect response enables it.

concepts

  1. Timing API Probe

    Inspect PerformanceResourceTiming entries for cross-origin resources. See which fields are populated vs. zeroed out based on whether the server sent Timing-Allow-Origin.

  2. Redirect Chain Demo

    A visual diagram of how timing data flows through a cross-origin redirect chain — with and without the opt-in header.

references

implementation reference

Need the exact API surface, compatibility boundaries, errors, lifecycle, and source links? Read the matching gendn reference ↗