Software testing is an important part of the entire software development process. The aim of this process is to evaluate the software to determine if the software meets the needs of the end user. It also helps in checking if the software is fit for the purpose intended and is defect free. At different stages of software development, there are different types of testing, which are used. To understand the difference between end-to-end and system testing debate, we will first understand what is end-to-end testing and system testing. What is End-to-End Testing? The type of testing which is used to validate the flow of the application from the start to the end without a glitch is called end-to-end testing. A real time environment is created for this testing process. It helps in assessing the interaction of the software with the database with other hardware applications or systems or within the software itself. In this process, the entire application is tested to find whether there is a glitch in any part of the software. When a defect is detected in the system and is fixed, end-to-end testing is carried out to ensure new defects have not been introduced in the system. In a number of organizations, end-to-end testing is the testing which is carried out from the first stage of software testing to the last stage of software testing. What is System Testing? System testing is used to validate that the software developed is in accordance with the requirements of the end user. Different modules of the software are validated in the process, taking into account the performance of the system as a whole. In other words, the entire system is validated as a whole. Defects are unearthed in the system as a whole and not in individual components which make up the system. The aim of system testing is to test the system from a user perspective, taking into account how the user will feel about the system and how convenient is it to use the system as a whole. End-to-End Testing Vs. System Testing When end-to-end testing is carried out, it is the flow of activities in the system starting from scratch to the end of the system which are tested. On the other hand, in system testing, the system as a whole is tested to find defects, if any, in the system. In most cases, end-to-end testing is carried out after changes have been made to the system, while system testing is carried out towards the end of the software development, where the application is validated against the requirements of the end user. To explain the difference between end-to-end testing and system testing further, we can take an example. If an email page is being tested, the starting point in end-to-end testing is logging into the page, while the end point is when you log out of the page. On the other hand, system testing is when you work through entire system, like logging into the system, sending an email, opening an email, replying to an email, forwarding the email, etc., and finally logging out of the system. Any defects in moving from one component to another and the working of the component itself is the aim of system testing. Therefore, end-to-end testing is often considered to be a subset of system testing. Often end-to-end testing and system testing are considered to be the same. However, from the above discussion it is clear that both of them are different from the other. More than the difference between end-to-end and system testing, it is important to note that both of them have an important role to play in the entire process of software testing. Using both of them a number of defects in the testing can be unearthed.