I guess it depends on the software that you are writing and how it's structured. The testing pyramid seems to make some sense, as long as you realize that you n

I guess it depends on the software that you are writing and how it's structured. The testing pyramid seems to make some sense, as long as you realize that you need a multitude of different tests for checking various things. For example, when writing a library that dealt with JWT and called into some other libraries, I opted for a lot of unit tests, I think the code coverage was around 90-95%. Writing tests for almost all of the functionality helped me actually discover one or two bugs which I could immediately fix without having them be released. Also, tests acted as documentation there, showing various use cases for the library, in addition to helping me actually make the API more user friendly. Integration and UI tests are also useful to see how the solution fares in the real world, but once you have to automate a browser or deal with mocking the DB (if you can't spin up a container, migrate the schema and seed it with real data for your tests), the complexity skyrockets. You might still want to have them and plenty of them, but at the same time you'll deal with slow and flaky tests more often, especially if the tech you choose or are stuck with won't support your needs all that well (e.g. Selenium). It's even worse if the thing you're testing changes a lot. As long as you have a staging environment, you should be even well off for anything from load testing to even the occasional bit of manual/acceptance testing, or trying to reproduce issues there. With the help of logs/metrics you can reason about changes/bugs/reproduction scenarios more safely, without impact on prod. Even better with other supporting things, like feature flags. Test whatever you can: sometimes the limiting factor will be time, other times the complexity of the system (or how testable it is in the first place, e.g. no fixed element IDs in a web browser), other times you won't get the infrastructure, but it's still a nice pursuit.