Best Practices for End to End Testing in Software Projects

Hi everyone,

I’ve been exploring ways to improve software quality in my projects and wanted to start a discussion about end to end testing, especially for applications with multiple services, frontend interfaces, and backend components. For those who want a solid conceptual foundation, this guide on end to end testing is very helpful.
In many modern software systems, unit tests validate individual functions and integration tests check interfaces between modules — but only end to end testing can verify that complete user workflows function correctly when all components interact together. This is especially important in complex applications where data flows through many layers before reaching the final output.
A few examples of typical end to end test scenarios include:

• User login and session handling across services
  
• Ecommerce checkout process with payment integration
  
• Data processing flows that span multiple microservices
  
• API driven workflows with external dependencies
  

I’d love to hear your thoughts on a few questions:

1. What tools do you use for end to end testing?
   Do you prefer UI automation tools like Cypress or Playwright, API testing frameworks, or something else?
   
2. How do you structure and organize your end to end test suites?
   For example, by feature, by user journey, or by system integration flow?
   
3. How do you balance comprehensive coverage with CI/CD speed?
   End to end tests are powerful but can be slow. How do you decide what runs on every push versus nightly builds?
   
4. Any tips for dealing with flaky tests?
   What techniques or strategies help keep your test suites reliable and maintainable?
   

I find that focusing on the most critical user journeys and automating them within CI workflows helps catch serious regressions early. But I’d love to compare experiences and learn what has worked well for others in this community.
Looking forward to your replies!