OS X used to have a "Network Link Conditioner" that shipped with XCode, I believe. It did a lot of the things you're suggesting, but right at the network inter

OS X used to have a "Network Link Conditioner" that shipped with XCode, I believe. It did a lot of the things you're suggesting, but right at the network interface level. Unfortunately, it broke with the advent of Mavericks. No idea whether it works now, or even still exists. On the last web-app project I worked on, we had a middleware that activated automatically in dev mode and just inserted a delay in every request to bring a local delay up to our users' median delay. It was intentionally a bit of a pain to turn off, so almost everyone ran in that mode.