Canary Deployment

Canary deployment is a release strategy where a new version is rolled out to a small percentage of users or servers first — the "canary" — while the rest keep running the old version. You watch error rates, latency, and business metrics on that slice; if the canary stays healthy, you gradually widen the rollout to 5%, 25%, 100%. If it misbehaves, you route traffic back and only that small group was affected. The name comes from the canary in a coal mine. Unlike blue-green deployment, which flips all traffic at once between two full environments, canary shifts traffic incrementally, so you catch regressions with real production traffic before they hit everyone. For AI/SaaS builders it's the safest way to ship risky changes — a new model version, a pricing-page rewrite, a different query path. Practical note: canary only works if you have real-time observability on the canary cohort and an automated rollback trigger; deploying a canary you can't measure gives you the risk without the safety.