They allow regular expression. But having use Django's regex matching a lot, and the one provided with werkzeug, I can tell you the second one is much more pro

They allow regular expression. But having use Django's regex matching a lot, and the one provided with werkzeug, I can tell you the second one is much more productive: 99% of the case you don't need a complex pattern and you are very happy to be able to just say "hey gime 'stuff' here" instead of crafting things like "(?P<stuff>\d+)" . For the rare use case, you just fall back on regexes.