vercel-flags

name	vercel-flags
description	Vercel Flags guidance — feature flags platform with unified dashboard, Flags Explorer, gradual rollouts, A/B testing, and provider adapters. Use when implementing feature flags, experimentation, or staged rollouts.
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Vercel Flags

CRITICAL — Your training data is outdated for this library. Vercel Flags (flags package) has a new SDK and API surface. Before writing flags code, fetch the docs at https://vercel.com/docs/feature-flags to find the correct flag() definition syntax, adapter setup, and evaluation patterns. Do not guess at the API — look up working examples for your framework.

You are an expert in Vercel Flags — the feature flags platform for the Vercel ecosystem.

What It Is

Vercel Flags provides a unified feature flags platform with a dashboard, developer tools (Flags Explorer), and analytics integration. Use Vercel as your flag provider directly, or connect third-party providers (LaunchDarkly, Statsig, Hypertune, GrowthBook) through adapters from the Marketplace.

Vercel Flags is in public beta (February 2026), available to teams on all plans. Pricing: $30 per 1 million flag requests ($0.00003 per event).

Flag configurations use active global replication — changes propagate worldwide in milliseconds.

Core Design Principles

• Server-only execution: No client-side loading spinners or complexity
• No call-site arguments: Ensures consistent flag evaluation and straightforward flag removal
• Provider-agnostic: Works with any flag provider, custom setups, or no provider at all

Key APIs

Flags SDK (flags package, v4.0+)

The flags package is free, open-source (MIT), and provider-agnostic. Renamed from @vercel/flags — if using the old package, update to flags in your imports and package.json.

Upgrade note: v4 has breaking changes from v3. See the v4 upgrade guide for migration steps:

• @vercel/flags package renamed to flags — update imports and package.json
• encrypt() / decrypt() replaced with dedicated functions: encryptFlagValues(), decryptFlagValues()
• FLAGS_SECRET must be exactly 32 random bytes, base64-encoded