TWRP full form of team win recovery project has been released for Samsung galaxy s4 mini. This feature will allow you to install custom ROMs; perform root on your S4 mini and so on. Since it has two models GT-I9195 and GT-I9190, make sure to install the right one for right variant.
Flash it using ODIN on your computer.
All of those builds are stable and work perfectly. To flash it put your S4 Mini in download mode (volume down + home button simultaneously); connect to computer and flash using ODIN.