Is StableMoney legit for FDs?

Is stablemoney app legit for FDs in small banks? How is your review using it for those who used it? I know that the amount is deposited directly into banks and app is only mediator and that 5lac sum is insured by RBI. But other than that how is your review using it. Are there some hidden charges? Is opening FDs without having an account in the bank even possible?