Work out shadow deployment traffic instantly with clear inputs, formula shown and shareable results.
Shadow deployment sends a copy of live traffic to a candidate model without returning its answers to users, so you get production-distribution behaviour with zero blast radius. The cost is real capacity: mirroring 20 percent of traffic means provisioning 20 percent more inference. Total mirrored volume determines whether the run collects enough events to compare distributions with confidence.
Shadow traffic
shadow rate = production rate x mirror share; total requests = shadow rate x duration in seconds; cost = requests x price per million / 1e6
Shadow mode carries no user risk because outputs are discarded, so it is the right first step for a model whose failure modes are unknown. A/B testing follows once you trust it enough to serve.
Prediction distributions, latency percentiles, error rates and agreement with the incumbent. Business metrics need an A/B test because shadow outputs never influence users.