In practice, is there any difference? As long as example.com is guaranteed to be reserved, I don't see any downside in using it.

Not using .test was a big problem for tools like Pow a while ago, but that's because they were using .dev, which had no official recognition as being reserved or special-purposed.

For e-mail addresses in particular, I could easily see a situation where your domain logic prevents you from using an invalid TLD (like .test), and it would be a shame to special-case something strictly for testing purposes.

Probably not, but it's always nice to follow intended designs, since others will do so as well and this allows systems to evolve in compatible ways. There may be no difference today, but there could be tomorrow.

These days invalid TLDs don't really exist. New ones are getting released all the time. The only problem you'd run into is if the system you're using is treating .test differently for some reason, but that's likely not the case, for obscurity reasons if nothing else.

.invalid is guaranteed invalid by spec.

Touche

> In practice, is there any difference?

RFC 6761 says that there is a difference when I actually resolve these names. The example.com, example.net, etc. will resolve normally to an existent IP. Moreover they resolve the same way on every DNS cache.

The xxx.test will resolve as non-existent by default, unless you configure your own DNS specifically for them.

> unless you configure your own DNS specifically for them

or use horrible ISPs that redirect everything that isn't valid (and intercept DNS if you try to use an alternate DNS).

I stand corrected

Well, example.com resolves, . test doesn't. Depending on your use case, one or the other may be desirable, but if you're setting up a dev environment, .test is your answer.

I've used example.com in the test cases of my webscraper. When they changed the links on the page, the test cases were failing, and I complained to them, but they did not care