Hey Jerome, it's based on a pair by pair basis.
After getting feedback from the community we'll be updating everything and relaunching.
I understand it depends on pair by pair basis, but you need to indicate the limits on the swap page right before a trade enters the values he is trying to swap. I believe this was missing out at the time I checked out the swap page. I do hope that in the coming update you add such vital features, among other things suggested by other members. As of now, I see a message about maintenance.