End-to-End (E2E) Testing is a software testing methodology that aims to validate the functionality and performance of an application from start to finish, ensuring that all components and systems work together as expected in a real-world scenario. This type of testing involves simulating a complete user journey, covering all possible interactions with the system, including the front-end interface, backend processes, and integrations with other systems or services. The goal of E2E testing is to identify issues that may not be evident when testing individual components in isolation, ensuring that the entire application works as intended when all parts are combined.

E2E testing is particularly important in complex, multi-tier applications where various subsystems need to work together seamlessly. By testing the entire workflow, E2E testing helps to uncover bugs related to data flow, user interface functionality, network communications, and integration points. It also ensures that business processes are correctly implemented and that any changes to the system do not break existing functionality. E2E testing is often automated to increase coverage and efficiency, allowing teams to detect issues early in the development process and reduce the risk of failures in production