Web Services technology is one of the most significant Web technologies in these days. There are challenges in order to conduct the web service testing. This paper will present the most popular web service testing challenges and the comparison of the popular open source testing tools: soapUI, Jmeter and REST Console. The comparison may give readers an informative overview with potential benefits of open-source testing tools, and also help in promotion and development of open-source testing tools. These tools will be comparing in terms of features, output result and the response time.