Selenium 2 (the Google "Webdriver" stuff) works quite well and isn't specific to Java in any significant way. If you can bring up your UI with a bunch of mocks

Selenium 2 (the Google "Webdriver" stuff) works quite well and isn't specific to Java in any significant way. If you can bring up your UI with a bunch of mocks/stubs under it, Selenium is a great way to do automated regression testing of your web UI. On your API design comments: My issue with TDD is that it's implicitly big-design-up-front. I used to think I understood a problem before I stated coding, but I don't anymore. So, anything I design in the beginning ends up being modified (if not scrapped entirely). There's no better way for me to understand a problem than by trying to solve it. Also, for important enough APIs (public stuff, widely used in a codebase, or whatever), the design of the API is dependent on the problem being solved. Let's say you are building an API for a yet-to-be-developed photo storage SaaS. For any solution of significant sophistication, can you really think through all the issues that have API design implications before attempting to create the service itself? Is it better to stream back the bits of a photo found via a tag search or should a "ticket" in the form of a GUID be provided instead? I don't know, but I'll have a better idea once I spend some time solving the problem.