Tanpura helps with Shadaj and Pancham. It is difficult to check our swaras.
I use this too. Called shruti. There is a hindustani version also of same name based on 22shruti principle
@vinodt1347 there is Shruti Carnatic Tuner by Kuyil the carnatic app. The hindustani one is just shruti tuner by prashant punde. I find the former better. I don't think there are exact standards in any Indian tuning