What should I use to develop on STM32 ?

Up to now there is a loot of IDE (Compiler and Debugger) for the Cortex Mx, in this page there is a little list of the principal IDE that are used for develop on the STM32.

In addition to the development environment is also necessary JTAG or SWD emulator that is normally provided by the vendors listed above and also directly by STM (ST-LINK).
There are, of course, other vendors that offer compatible JTAG/SWD emulators with leading development environments.

IMPORTANT:
All the STM32 library is release in ANSI C and CMSIS so is it possible use it under all C-Compiler (IDE).
The toolchain directly supported by STM also contain the configuration files of themselves.

• Free IDE for STM32
  • STM32CUBE-MX or STM32CUBE-IDE is the configurator and a complete IDE also for debug (STM32CUBE-IDE)
    • mBed is free ARM compiler – See  my tutorial here
    • ATOLLIC now is integrated inside the STM32CUBE-IDE
    • KEIL is free for STM32L0xx (Cortex M0+), STM32G0xx (Cortex M0+) and STM32F0xx (Cortex M0).
      For other STM32 it is free up to 32K of exe.
    • emIDE
    • AC6 – System WorkBench
    • Now is possible use some STM32 in the ARDUINO IDE.
      For more info see this tutorial.
      .
• Paid IDE – Paid IDE there are a lot and is impossible list all. Below there are the principal IDE.
  • IAR
  • KEIL
  • ATOLLIC
  • CrossWorks
  • Raisonance
  • MikroElektronika – mikroC, mikroBASIC and mikroPASCAL

• High level language
  • MicroEJ (Java) is a leading vendor of cost-driven embedded software solutions for the smart digital world.
  • MicroPython – Here there are the FW ready to use on different STM32 boards.
  • MATLAB and Simulink are here.
    .
• Our suggested KIT for developing on STM32
  • STM32CUBE-IDE + STM32CUBLE-PROG + ST-LINK
  • KEIL that is free only for STM32F0/L0/G0
  • ST-LINK-Utility – More info concerning ST-LINK-Utility, ST-LINK emulator, etc, are here.
  • STM32CubeMonitor – Helps debug and diagnose STM32 applications while they are running by reading and displaying their variables in real-time.
  • Tera-Term – This is useful if you need to use the USB virtual com
  • ST-MCU-Finder (for select the right STM32 to use)
  • Download and unzip the library of the STM32xx that you want to use.
    Inside the library there are a loot of examples ready to use.
  • Last but not least, we suggest you to start to develop using the:
    • STM32-NUCLEO
    • STM32-Discovery
    • STM32-Evaluation Boards