Progressive rollouts release new functionality gradually by incrementing the percentage of subjects exposed to the feature over time. Canaries are progressive rollouts that monitor guardrail metrics and automatically pause or stop when they detect regressions.

Progressive rollouts

Configure a progressive rollout

1. Navigate to your feature flag and open Targeting Rules & Rollouts for the target environment.
2. Click Add Targeting Rule and select Add Rollout Steps to create a multistep rollout.
3. Configure rollout steps:
   • Customize the percentage for each step, and add or delete steps as needed.
   • Change the delay between steps for a slower or faster rollout.
   • Click Split Traffic to roll out multiple variants at the same time.

Start and control the rollout

1. Enable the flag in the environment so SDKs evaluate your targeting rules.
2. Click Start Rollout to kick off the progressive rollout.

After the rollout starts:

• Click Pause Rollout to stop progress temporarily.
• Click Stop Rollout to revert all progress on the rollout.

Monitor progress with evaluation tracking and configure notifications for rollout events.

Canaries

A canary is a progressive rollout that includes guardrail metrics. Guardrail metrics measure standard key performance indicators (KPIs) such as error rate and long task count.

How canaries work

When guardrail metrics are configured, the rollout monitors metrics in both groups:

• Treatment: Subjects receiving the variant you are rolling out
• Control: Subjects not receiving the treatment variant

When the canary detects a statistically significant change in any guardrail metric, it automatically pauses or stops the rollout.

Configure a canary rollout

1. Create a progressive rollout targeting rule as described in the Configure a progressive rollout section.
2. Add guardrail metrics to the rollout configuration.
3. Choose whether guardrail failures should pause or stop the rollout.

Best practices

• Configure notifications on the flag to be alerted when the rollout starts, pauses, or stops.
• For canaries, notifications fire when a guardrail metric pauses or stops the rollout — configure these before starting the rollout so you’re alerted immediately if a regression is detected.
• Use evaluation tracking to monitor how many subjects are receiving each variant as the rollout progresses.