Keys, visibility, and evaluation

Superflag separates who may manage configuration from where configuration may be delivered. Treat the prefix as a credential class, not as the complete authorization check.

Key	Scope	Use it for	Never expose it to
`pub_`	One environment	Browser, React Native, and Expo config delivery	N/A; it is a public identifier, but still has environment-scoped authority
`sdk_`	One environment	Trusted server config, local server evaluation, remote evaluation, OFREP	Browser bundles, mobile apps, public env vars, logs, or responses
`admin_`	One app	Server-side management automation	Client code or untrusted systems
`cli_`	One user	CLI and user-owned management workflows	Client code, repositories, or logs

Server-only by default

Advanced flags and segments default to server visibility. A flag reaches a client only when it has visibility: "client". Every prerequisite and segment referenced by that flag must also be client-visible. Invalid dependency graphs fail closed instead of leaking a partial rule set. Legacy flags use clientEnabled: true. The client delivery route never includes legacy rules or overrides.

Choose an evaluation model

Model	Best fit	Tradeoff
Client SDK	UI flags and non-sensitive targeting rules	Delivered rules and comparison values can be inspected by the client
Node SDK	Trusted server, serverless, and edge code	Syncs the full configuration and evaluates locally
Remote evaluation	Sensitive rules that should remain in Superflag	Adds a network round trip to each uncached decision
Core SDK	You already possess a versioned config	No transport or remote synchronization is included

Stable targeting identity

Percentage rollouts and experiments need a stable targetingKey. Use the same logical subject for decisions that should remain in one cohort, such as a user, organization, workspace, or install. Put additional allow-listed targeting data under attributes.

{
  targetingKey: organization.id,
  attributes: {
    plan: organization.plan,
    country: organization.country,
  },
}

The environment privacy allow-list removes attributes that were not explicitly approved. Do not use random request IDs for a rollout that should remain stable.

Fallbacks are part of the contract

Every typed value read has a deterministic fallback. Choose the fallback as the safe product behavior when configuration is missing, invalid, unauthorized, or too old to serve.

await flags.isEnabled("new-checkout") // false fallback
await flags.getString("checkout-copy", "Continue")
await flags.getNumber("checkout-limit", 10)

Configuration sync pricing is per environment request, not per user. Both 200 and 304 config responses count as a sync; 304 avoids response bytes.

Start here

Node and server SDK

React SDK

React Native and Expo

Core SDK

CLI and agents

Feature decisions

HTTP API

Keys, visibility, and evaluation

Keys, visibility, and evaluation

Server-only by default

Choose an evaluation model

Stable targeting identity

Fallbacks are part of the contract

​Keys, visibility, and evaluation

​Server-only by default

​Choose an evaluation model

​Stable targeting identity

​Fallbacks are part of the contract

Keys, visibility, and evaluation

Server-only by default

Choose an evaluation model

Stable targeting identity

Fallbacks are part of the contract