Abstract
Software testing is the process of testing, verifying and validating the user's requirements. During whole software development, testing is an ongoing process. Black Box, White Box testing and grey box testing are the three main types of software testing. In Black box testing, user doesn't know intrinsic logics and design of system. In white box testing, Tester knows the intrinsic logic of code. In Grey box testing, Tester has little bit knowledge about the internal structure, code and working of the system. It is commonly used in case of Integration testing. Load testing is the type of testing which helps us to analyze the performance of the system under heavy load or under Zero load. With the help of a automated load Testing Tools, we can do it in better way. The intention for writing this research is to carry out a comparison of four automated load testing tools i.e. Apache JMeter, HP LoadRunner, Microsoft Visual Studio (TFS), Siege based on certain criteria i.e. test scripts generation, plug-in support, result reports, application support and cost. The main focus is to study and analyze these load testing tools and identify which tool is best and more efficient [10]. We assume this comparative analysis can help in selecting the most appropriate tool and motivates the use of open source load testing tools.