What Is a Canary Deployment?

A canary deployment is a controlled rollout strategy that involves pushing out changes to a small subset of users first before releasing to the rest of the user base. This pattern allows organizations to limit or avoid downtime, gather feedback on new code behavior in production, and easily roll back in case of bugs or performance degradation. Canary deployments are inspired by how canaries used to serve as an early warning for toxic gases down coal mines. They help test the new feature in production while minimizing impact to users. Some benefits include getting early feedback from real users on performance, bugs, and user experience before exposing all users to the new version, quicker rollback in case of significant errors, and reduced deployment stress due to lower stakes. However, there are also drawbacks such as two environments to maintain, technical challenges, support for multiple versions, and some errors not making themselves known on a user's first exposure to the new version.