Locust vs SoapUI

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.

SoapUI is an open-source tool for testing REST, SOAP, and GraphQL web services. It supports drag-and-drop creation of functional and regression tests, assertions, and data-driven tests, and can create service mocks from WSDL. The listed protocols also include JMS and SOAP/WSDL. Functional tests can be extended into load testing, including runs from command-line tools. Named automation integrations include Maven, Hudson, Bamboo, JUnit, and Ant, and SoapUI can run from other CI tools. It can configure incoming and outgoing WS-Security, including encryption, signatures, SAML, keystores, and truststores. SoapUI is described as cross-platform for Windows, Mac, and Linux/Unix. The open-source edition is listed for basic functional and performance testing; security testing appears among expanded capabilities associated with ReadyAPI. The listed SoapUI Open Source plan is free and includes API testing, mocking, and command-line automation. SmartBear describes it as a starting point for developers and testers, with support and a community forum linked on the site.