Mocking authentication in software development allows for faster testing, reduced infrastructure costs, and simplified testing flows that rely on external systems. However, it's essential to determine when mocking is justified and when it might introduce risks or gaps in testing. The article provides guidance on identifying scenarios where mocking auth makes sense, such as bypassing the login flow entirely, simulating edge cases or error scenarios, or dealing with large system complexity. When mocking auth doesn't make sense, it's often due to highly regulated environments, systems with strict security requirements, or contexts where real-world behavior is needed. In these situations, integration tests that validate real tokens and include MFA flows are recommended instead. The article concludes by emphasizing the importance of knowing when to use mocking auth and being mindful of its limitations.