Vercel Flags SDK cuts cold-start initialization time and stops usage reporting from extending function duration
Vercel's changelog reports that @flags-sdk/vercel now loads the bundled flags datafile at client creation, removing a network wait during cold-start initialization. Usage reporting was changed to pass events to the Vercel runtime instead of using waitUntil, so it no longer extends function duration; users are told to update to version 1.5.3 or later and redeploy.
Why it matters
Builders running feature flags on Vercel Functions may see lower cold-start overhead and no added function duration from usage reporting, which can affect latency and billed execution time. Vercel's figures are from internal testing: p75 cold-start SDK initialization dropped from over 70 ms to 10 ms, and p99 flag-read latency is under 1 ms across cold and warm invocations.
Who should care
Developers and teams using Vercel Flags or the Flags SDK with Vercel Functions, especially those sensitive to cold-start latency.
What you can do
Update @flags-sdk/vercel to version 1.5.3 or later and redeploy your application.