Configure weighted traffic splits for Vercel Flags from the Vercel CLI

Vercel introduced functionality to configure weighted traffic splits for Vercel Flags directly through the Vercel CLI, enabling developers to control what percentage of traffic sees different flag variations without using the web dashboard. This feature allows for more granular A/B testing and gradual rollouts of features by distributing user traffic across multiple flag values according to specified weights.

Source: Vercel Blog | 2026-05-21