FEATURE FLAGS

Ship code. Control rollout.
No redeploy required.

Wrap any code path in a flag and control it from the dashboard. Instant toggle, no deployment needed.

How it works

Name your flag and set a default value — what the SDK returns when no targeting rules match.

Define who sees which value. Target by segment, user attribute, or roll out to a percentage. Rules evaluate in order.

Deploy your code with the flag check in place. Enable, disable, or adjust rollout percentage from the dashboard — instantly.

The standard on/off flag. Returns true or false. Use for feature gates, kill switches, and targeted rollouts.

Simple check

if (flaggy.isEnabled('new-checkout')) {
// show new checkout
}

With context

flaggy.isEnabled('new-checkout', {
  key: 'user-123',
  plan: 'pro',
  country: 'DE',
});

Client-side evaluation

The SDK downloads your flag rules and evaluates them locally. No network request on every flag check — evaluation is a fast in-memory lookup.

Instant toggle

Enable or disable a flag from the dashboard and it propagates across your SDK instances within seconds. No deployment, no cache flush needed.

Default values

Every flag has a default that's returned when no targeting rule matches, or when the SDK can't reach Flaggy. Your code always gets a value.

Environment isolation

Flags are configured per environment. A flag can be enabled in staging and disabled in production — rules and values are independent per environment.

Percentage rollout

Roll out to 5% of users, check your metrics, then increase to 25%, 50%, 100%. The SDK ensures a user always gets the same variant once assigned.

Free plan available. No credit card required.