Two versions, one project
FastECU is the original, mature desktop application (Qt/C++) - free and open source under the GPLv3, source available on GitHub. It's the stable choice today: read, tune, and flash a supported ECU or TCU, recover a bricked unit via bench mode, and log live data while driving.
FastECU NextGen is a from-scratch rewrite in React/TypeScript, built to be cross-platform from day one - including macOS, which the original never supported. It's not a straight port: some things (real OS clipboard, editing more than one ROM file at once) are already better than the original, others are still catching up. Subscription access is opening soon; no pricing is set yet.
Who it's for
Subaru owners and professional tuners working on Forester, Impreza, Legacy, and BRZ platforms spanning 1999-2000 K-Line ECUs through 2013+ CAN-bus vehicles - anyone who needs to read a stock calibration, write a tune, or recover a unit that a bad flash left bricked.
Off-road/competition use only. FastECU is intended for vehicles used off-road or in closed-course competition. Modifying a vehicle's calibration can affect emissions compliance and road-legal status - you're responsible for complying with the laws in your jurisdiction.