What is Canary Deployment?

What is Canary Deployment?

Canary deployment releases a new version to a small percentage of users before making it available to everyone. If system metrics and user behavior remain healthy, traffic is increased gradually.

For example, a new checkout flow may start with 1% of users, then 10%, then the full audience. If error rate, latency, payment success, conversion, or support tickets move outside expected thresholds, the rollout can pause or roll back.

How Is It Different from Blue-Green?

Blue-green deployment focuses on switching traffic between two production-ready environments. Canary deployment focuses on spreading risk gradually across the user base. The two can be combined: prepare the new environment, then increase traffic in canary steps.

Canary releases depend on observability, alert thresholds, and rollback rules. Technical metrics are not enough on their own; business metrics matter too. An application may be technically healthy while checkout completion, signup, or search success drops.

Feature flag systems make canary rollout more flexible. A feature can be enabled by user group, country, plan, or account while the code is already deployed.