Response Time
// Definition
Total time from request initiation to response completion. Includes latency plus transfer and processing time. The end-user-perceived performance metric.
// Related terms
Latency
The time between sending a request and receiving the first byte of response. Lower is better. Often reported at percentiles (p50, p95, p99) since averages hide tail behaviour.
Throughput
The amount of work completed per unit of time — requests per second, transactions per second. Higher is better.
Load Testing
Verifying system behaviour under expected production load. Confirms the application meets performance targets at typical concurrent-user counts before release.
Learn more · Non-Functional Testing Overview
Chapter 2 · Lesson 2: Key Performance Metrics — Response Time, Throughput, Latency