Software testing has become almost the most important phase of software development. In recent years, several testing tools have been developed to accomplish the testing phase of the project. Most of these products cannot perform software testing in very large scales. Testing as a Service (TaaS) is the latest solution that has been proposed for this problem. It is a specific type of Software as a Service (SaaS) that performs software testing. It will be launched over the cloud environment and uses cloud’s unlimited resources to test software in any scale. The goal of the TaaS is to create an application that is very scalable and flexible in testing. This book explains the procedure of designing a framework for TaaS that supports functional, performance and scalability testing for online and offline applications.