Vercel Flags removes a cold-start network wait

Vercel’s Flags SDK now parses the deployment’s bundled flag data when the client starts and checks its revision from invocation metadata, avoiding a cold-start network request. Vercel reports internal p75 initialization dropping from over seventy milliseconds to ten. Usage events also pass through the runtime instead of keeping the function running after its response; these changes target flag initialization and reporting, not entire application latency.

Vercel · Oct 29, 2026

Why it matters

Removing a synchronization request can improve startup, while moving bookkeeping can change billed execution independently of response time.

More context

The October 29 notice requires @flags-sdk/vercel 1.5.3 or later and redeployment on Vercel. Test a flag change as well as a cold invocation so the update path and initialization behavior are both covered.

Keep in mind

The timing is Vercel’s internal measurement, not a guaranteed sevenfold application speedup. The announcement does not establish equivalent behavior on other hosting platforms or provide a workload-specific cost estimate.

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