SoapUI is an open-source web service testing application for service-oriented architectures (SOA) and representational state transfers (REST). Its functionality includes web service inspection, invoking, development, simulation and mocking, functional testing, load and compliance testing. Developed by SmartBear Software
License: Open Source
Insomnia is a user-friendly tool primarily designed for RESTful APIs, making it ideal for developers looking for quick and efficient API testing. In contrast, soapUI offers extensive support for both SOAP and REST services, along with advanced testing features, making it more suitable for enterprise-level applications and complex testing scenarios.