Q: Using angular service inside each other Do you know if it's possible to use angular services inside each other? I tried it but getting error "Circular dependency found". For example I have two services A and B. Can I use service A inside service B and service B inside service A ?

A: No , you cant do it with basic angularjs dependency injector, but you can retrieve any service with $injector
https://docs.angularjs.org/api/auto/service/$injector
so can "lazy" load it to any var, and access it in other service.... but you should post some code.
Also it is smell like you are anti patterning something , or you have bad architecture when you have circular dependencies. Its like on the road :
Assume you have 2 Services
Foo Depends on Bar
Bar depends on Foo

Angular will go as this
Foo -> Depends on bar so load Bar -> Instantiate Bar but its depends on Foo so instantiate Foo -> Instantiate Foo but it depends on Bar but wait! Bar is still not instantiated because it waiting for Foo , so its cyclic. 
You should have service
Foo with no dependency
Bar with no dependency

and Third factory 
FooBar which will handle functions which needs the circular dependency.

