ApacheBench (ab) vs Locust

ApacheBench (ab) has no write-up on Specifiction yet; its figures are above.

Locust is an open-source performance and load testing tool for HTTP and other protocols. Test scenarios are written in Python, with regular Python libraries available for use within them. Tests can run from the command line or web interface, which displays throughput, response times, and errors in real time; results can be exported for later analysis. The interface shows progress and lets users change load during a run. Locust can distribute tests across multiple machines and says it can support hundreds of thousands of concurrent users. Other systems and protocols can be tested by adding a client, and documentation lists community extensions for protocols and reporting. Optional OpenTelemetry support exports traces, metrics, and logs to compatible backends such as OTLP, Prometheus, Jaeger, and Tempo. Automatic instrumentation currently covers the requests library. Installation is documented with pip install locust or uvx. Locust is free and MIT-licensed. Its documentation also describes hosted load testing through Azure Load Testing, with reporting, Application Insights integration, and CI/CD support for Azure DevOps and GitHub Actions.