Throughput
Throughput is the number of requests, transactions, or operations a system can process in a given period of time — typically measured in requests per second — describing overall system capacity rather than the experience of any single request, which is what response time and latency measure instead.
Throughput and response time can move independently of each other and even trade off against each other — a system can have high throughput with individually slow responses (many things happening in parallel, each taking a while) or low throughput with fast individual responses (few things happening, but each one quick).
Understanding both together matters for capacity planning: a payments system needs both — reasonably fast individual response times (users won't wait long) and enough overall throughput to handle Black-Friday-level simultaneous transaction volume — optimizing for only one of the two gives an incomplete picture of real readiness.
