---
title: Vercel Flags
description: Control feature releases with environment-specific targeting, rules, and gradual rollouts.
url: "https://vercel.com/kb/vercel-flags"
published: 2026-10-01
last_updated: 2026-10-01
install_vercel_plugin: npx plugins add vercel/vercel-plugin
---

# Vercel Flags

Control feature releases with environment-specific targeting, rules, and gradual rollouts.

## All Vercel Flags guides

- [A/B testing on ecommerce storefronts without hurting Core Web Vitals](/kb/guide/ecommerce-ab-testing-core-web-vitals): Client-side A/B tools can worsen LCP and CLS on the pages you're testing. Run ecommerce A/B tests at the edge with Routing Middleware and Vercel Flags.
- [How Vercel Flags are evaluated](/kb/guide/how-vercel-flags-are-evaluated): Learn how Vercel Flags determines a flag’s value across environments using evaluation context, targeting, rules, and fallback outcomes.
- [How Splits Work in Vercel Flags](/kb/guide/how-splits-work-in-vercel-flags): Use weighted splits in Vercel Flags to deterministically bucket users into variants by percentage for gradual rollouts and A/B testing
- [How to use Vercel Flags across projects](/kb/guide/how-to-use-vercel-flags-across-projects): Evaluate flags across projects using a source project SDK Key in the consumer project via a custom adapter
- [How Vercel Flags resolves environments](/kb/guide/how-vercel-flags-resolves-environments): Configure Vercel Flags per environment by using environment-scoped SDK Keys that map your Vercel deployment environment to the correct flag environment

## Explore other topics in the Vercel Knowledge Base

- [Jev from TypeSafe AI](/kb/jev-from-typesafe-ai): Jev is TypeSafe AI's System One model for fast, typed decisions. It evaluates supplied context and returns choices, scores, and probabilities that applications can use to classify requests, route tasks, and assess proposed actions without generating prose.
- [Vercel Sandbox](/kb/vercel-sandbox): The compute primitive designed to safely run untrusted or user-generated code on Vercel.
- [FDE Field Notes](/kb/fde): Insights from our work with customers. Explore the patterns, diagnostics, and recommendations Vercel’s Forward Deployed Engineers use in production.
- [Software Factory](/kb/software-factory): Software factories put an agent on every stage of your development loop: triage, planning against a live repo checkout, implementation verified with your own checks, and independent review. Work items become draft PRs while you keep the judgment calls.