According to the Scrum Guide, the Scrum Team consists of one Scrum Master, one Product Owner, and Developers. There is no distinction between different types ofDevelopers, such as testers, programmers, designers, etc. The Developers are the people who deliver a potentially releasable Increment of "Done" product at the end of each Sprint. They are accountable for creating and adhering to the Definition of Done, ensuring technical excellence and good design, and collaborating with the Product Owner to maximize value1.
Therefore, everyone on the Scrum Team is responsible for ensuring the quality of the product, and there is no specific tester role. However, this does not mean that testing skills are not needed or valued. On the contrary, testing is an essential activity that supports the team and critiques the product throughout the development process2. A professional tester can contribute to the Scrum Team by coaching the team on testing techniques, tools, and practices, helping the team to define clear and unambiguous acceptance criteria, challenging the team to consider different scenarios and edge cases, creating and executing test plans, and providing feedback on the product's usability, performance, security, and other aspects3. A professional tester can also collaborate with the Product Owner to ensure that the product meets the expectations and needs of the stakeholders and users.