Developer tools

Release control that reads like application code.

Typed JavaScript and React SDKs for flags, detailed evaluations, experiments, and survey delivery—with a small API surface and predictable fallbacks.

Read the quickstart Create an API key
Install
npm install @fujiflag/jsnpm install @fujiflag/react
ESMCommonJSBrowserNode
import { createFujiFlagClient } from
 '@fujiflag/js';

const client = createFujiFlagClient({
 apiKey: 'ff-pk-your-key',
 cacheTTL: 5 * 60 * 1000,
});

const checkout = await client.getFlagValue<boolean>(
 'new-checkout'
);

Designed for the code path

Small primitives. Enough context when you need it.

Use a value-only API in ordinary UI code, then switch to detailed evaluation where analytics or debugging needs the decision metadata.

Type-safe values

Boolean, string, number, JSON, and generic return types.

Configurable caching

Choose a cache TTL that fits the sensitivity of each application.

Optional polling

Refresh flags on an interval without wiring a second state system.

Read-only clients

Public evaluation keys cannot mutate workspace configuration.

Choose your integration

The same evaluation contract, with the ergonomics your app expects.

JavaScript SDK

@fujiflag/js

A framework-agnostic client for browser, Node.js, ES modules, CommonJS, and script tags.

  • Single and bulk flag reads
  • Detailed experiment evaluation
  • Evaluation context
  • Survey runtime and custom renderer
View package

React SDK

@fujiflag/react

A provider and focused hooks that keep evaluation state natural inside React applications.

  • FujiFlagProvider
  • useFlag and useFlags
  • useFlagEvaluation metadata
  • Survey delivery hook and host
View package

Start small. Ship safely.

Get from install to first evaluation.

Create a free workspace, copy the environment read key, and add FujiFlag to an existing JavaScript or React application.

Create your free workspace

No credit card required.