Let's say I have a route '/foo/bar/baz'. I would also like to have another view corresponding to '/foo' or '/foo/'. But I don't want to systematically append trailing slashes for other routes, only for /foo and a few others (/buz but not /biz)

From what I saw I cannot simply define two routes with the same route_name. I currently do this:

config.add_route('foo', '/foo')
config.add_route('foo_slash', '/foo/')
config.add_view(lambda _,__: HTTPFound('/foo'), route_name='foo_slash')

Is there something more elegant in Pyramid to do this ?

Pyramid has a way for HTTPNotFound views to automatically append a slash and test the routes again for a match (the way Django's APPEND_SLASH=True works). Take a look at:

http://docs.pylonsproject.org/projects/pyramid/en/latest/narr/urldispatch.html#redirecting-to-slash-appended-routes

As per this example, you can use config.add_notfound_view(notfound, append_slash=True), where notfound is a function that defines your HTTPNotFound view. If a view is not found (because it didn't match due to a missing slash), the HTTPNotFound view will append a slash and try again. The example shown in the link above is pretty informative, but let me know if you have any additional questions.

Also, heed the warning that this should not be used with POST requests.

There are also many ways to skin a cat in Pyramid, so you can play around and achieve this in different ways too, but you have the concept now.