Feature flags

Release code without releasing control.

Decouple deployment from launch, choose who gets a feature, and increase exposure when the release is ready—not merely when the build is ready.

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Available now with boolean, string, number, and JSON flag values.

FujiFlag environment configuration screen for the Checkout Redesign feature flag

Capabilities

A safer path from merged to available.

FujiFlag gives small teams the release controls they usually have to build themselves, with predictable evaluation behavior across environments.

Environment values

Keep development, staging, and production behavior independent under a single flag key.

Context targeting

Match string, number, and boolean attributes with ordered rules and explicit fallback behavior.

Percentage rollouts

Release to a deterministic percentage of callers using an opaque targeting key and stable hashing.

Typed values

Use boolean flags or deliver string, number, and JSON values through the same evaluation contract.

Copy configuration

Move a reviewed configuration snapshot between environments instead of rebuilding rules manually.

Clear evaluation reasons

Know whether a value came from a target match, rollout, experiment split, or fallback.

Workflow

Deploy first. Release on your terms.

A flag becomes a small decision layer between shipped code and visible product behavior.

Create the flag

Choose a stable key, value type, and sensible fallback before the code reaches production.

Define the audience

Target internal users or customer contexts, then add a deterministic rollout when you are ready.

Expand or reverse

Increase exposure, change the served value, or return to the fallback without another deployment.

Built for implementation

Evaluation your application can explain.

The SDK can return the value alone or the value with the reason and experiment detail that produced it.

Read-only public API keys keep client applications scoped to evaluation.
Evaluation context is processed statelessly; targeting rules stay in the control plane.
Configurable caching and polling let each application choose its freshness tradeoff.
Missing attributes and targeting keys fall back predictably instead of guessing.

TypeScript

import { createFujiFlagClient } from '@fujiflag/js';

const client = createFujiFlagClient({
  apiKey: 'ff-pk-your-key',
});

const enabled = await client.getFlagValue(
  'new-checkout'
);

One platform