Canary release
A canary release routes a small percentage of production traffic (typically 1-5%) to a new version, monitors error rates and latency, and rolls forward to 100% only when metrics stay healthy. The name comes from coal miners' canaries — early warning of trouble.
Canary releases are richer than blue-green because they let you detect issues that only emerge under real production load (rare error paths, scale-dependent bugs, third-party integration regressions). The trade-off is operational complexity: you need traffic-splitting infrastructure (service mesh, load balancer rules) and observability robust enough to compare canary vs baseline error rates with statistical confidence.
Related terms
- Blue-green deploy
Blue-green deployment maintains two identical production environments — blue (current) and green (new).
- Feature flag
A feature flag is a runtime toggle that gates whether a code path is active.
- Continuous deployment
Continuous deployment automatically deploys every change that passes the test suite into production — no human gate between merging code and serving traffic.