What is E2E testing?

End-to-end (E2E) testing is a software testing methodology used to test an application's workflow from start to finish. The goal is to simulate real user scenarios and validate that the application's various components and dependencies function correctly together. It verifies that the entire system works as expected, ensuring data integrity and proper communication between different parts of the application, including databases, networks, and other external interfaces. E2E testing is commonly used to identify issues that might not be found in unit or integration testing, focusing on the overall user experience.