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Ship with control, not guesswork

Superflag is a feature flag and remote configuration system for React, React Native, Expo, Node, serverless, edge runtimes, CI, and agent-driven workflows. Configuration is evaluated deterministically through one shared core engine.

Flag anything

Use the same configuration model in browser, mobile, server, and edge code.

Safe for agents

Discover a machine contract, inspect state, plan changes, dry-run, and apply with CAS and idempotency.

Private by default

Server rules stay server-side unless you explicitly make every dependency client-visible.

Pay for syncs, not people

Configuration sync usage is counted per environment. Superflag does not use MAU or DAU pricing.

Choose a runtime

Node and servers

Networked SDK for Node 20+, Bun, Deno, serverless, and edge runtimes with standard fetch.

React

Typed hooks, resilient browser caching, and optional feature telemetry.

React Native and Expo

Expo-safe lifecycle handling, AsyncStorage caching, and Hermes-verified builds.

Core

Dependency-free schema, targeting, rollouts, privacy projection, experiments, and OpenFeature adaptation.

CLI

Manage flags, inspect impact, promote configuration, and automate experiments.

HTTP API

Config delivery, remote evaluation, management, telemetry, and OFREP endpoints.

The important boundary

Use pub_ keys only in browser or mobile applications. Use sdk_ keys only in trusted server environments. A flag is server-only by default; client delivery requires explicit visibility, including every prerequisite and segment it depends on.
Never put an sdk_, admin_, or cli_ credential in a browser bundle, NEXT_PUBLIC_*, EXPO_PUBLIC_*, an app response, a log, or persisted SDK cache.

Predictable failure behavior

SDK reads use explicit fallbacks. Valid last-known-good configuration can be served within a bounded stale window, concurrent refreshes are coalesced, ETags avoid redundant bytes, and authentication failures clear cached configuration. Evaluation never waits for optional telemetry delivery.

Integrate your first flag

Start with a client or server integration, then use the CLI to inspect and automate it.