The application in the DEMO version provides terminal functions. So you can test the USBserial, BT or BLE connection.
For usb you need a small OTG adapter. Should support popular converters like CP210x, FTDI, PL2303 i CH34x.
User can save his three commands to send them quickly without typing, but of course he can also type others on the fly.
For USB connections, user can select one of the predefined speeds or enter its own.
Bluetooth connections are handled at the speed to which the BT module (e.g.HC-05) is set to.
Running the programmer function requires a one-time license purchase
Terminal functions allow the user to become familiar with the application.
Supported BIN or HEX file formats can be opened from the device's memory, SD card or even by browsing your GDrive.
The application can automatically send a command to start the bootloader on the target device if one is provided for it (Soft reset).
The software files can be encrypted so you can then mail them to the customer or give them a link and it is possible that they will update the software themselves.
I can add support for other protocols (MkBoot/Arduino, etc.) because, for example, RAW is already there. An iOS version is also in the plan.