I learned of Runscope some time after I started building this, it looks very interesting.

I too have doubts a proxy service like debugproxy will be very successful as it is, mostly because using it is still very difficult and in some cases not possible on various devices (buggy proxy implementations on early iPhones, Android 7 not allowing root certificates to be added etc..)

I figured there are some other cool things you can do with a proxy though that might be interesting. For example getting remote debugging working smoothly by injecting a script into HTML pages sent through the proxy. Or going the other way and proxy existing websites through a sub-domain of debugproxy.com, which I used to do to demonstrate changes to clients websites.

I'll see what feedback I get in the coming weeks and decide what to do, if anything, from there.