What are end-to-end (E2E) system tests and what tools support them?

End-to-end tests drive the complete app in a real browser the way a user would, and tools like Cypress and Selenium automate them.

E2E tests are essential for serious production systems. They can be:

• Manual - testers interact with the application
• Automated - scripts simulate user actions

Popular tools:

• Cypress (cypress.io) - modern, developer-friendly
• Selenium (selenium.dev) - mature, supports many languages

Automated E2E tests verify the entire user flow from login to checkout, catching integration issues.