What Is Shadow Traffic?
Shadow traffic (or traffic mirroring) is the technique of duplicating live production requests and sending the copies to a new or candidate version, while discarding its responses so users are unaffected. The candidate handles realistic load and data, letting teams compare its behavior and performance against production safely.
Why it matters
Synthetic load tests rarely capture the messiness of real traffic. Shadowing exercises a new version against genuine production patterns with zero user risk, catching performance regressions and edge-case errors before the version ever serves a real response.
Related concepts
- Responses are discarded, so users are unaffected
- Complements canary analysis and dark launches
- Requires care with side effects like writes and emails
Related guides
What Is a Dark Launch?A dark launch ships a feature to production turned off or hidden, so it can be tested in the real environment…
What Is Canary Analysis?Canary analysis compares a new release serving a small slice of traffic against the stable version to decide…
What Is Progressive Delivery?Progressive delivery rolls out a change gradually to expanding audiences with automated checks, so issues sur…