So, I have this old app, and problem is that app is accessing old backend URL, which no longer exists.
How do I change this url without recompiling app? Is there any app which can redirect traffic of other apps to specific URL?
On Windows, Fiddler can do that.
My phone is not rooted so using hosts file to remap domain is not an option.
What you are asking for is man in the middle application. On google play there are a plenty of them, and some of them know how to modify request.
For example here: is mentioned that this application can modify request.