Saphire is a hardware-based external for Roblox. Instead of injecting code into the game or writing to its memory, the brain of the setup lives on a tiny chip you hold in your hands: an ESP32-S3.
Once flashed, the ESP32-S3 plugs into your PC and pretends to be a real physical mouse. It speaks genuine USB HID — the same language as the mouse on your desk. That is the entire point: the game cannot tell the difference, because there is none.
The rbx.exe backend runs on your PC, does all the reading and aiming math, and streams movement data to the ESP32-S3 over serial. The chip converts that into real mouse inputs, directly through the hardware layer.
Nothing is ever loaded into the game process. rbx.exe sits completely outside.
Inputs arrive through actual USB hardware — indistinguishable from your hand.
The firmware lives on the chip, not on your PC. Nothing to scan for.
Setup takes about two minutes: flash the firmware here, then launch rbx.exe. Ready?
Plug it in first: connect the USB cable from your PC to the port marked COM on the device — the label printed between the two female plugs tells you which is which. PC side goes to your computer, the other female plug stays free.
Your ESP32-S3 is now running the Saphire firmware. Leave it plugged in — it is the input path between rbx.exe and the game.
Launch rbx.exe (download it above). It will auto-detect the COM port of the ESP32-S3 and bind to it.
The device now enumerates as a real HID mouse. Everything rbx.exe sends arrives through genuine USB hardware.
Open Roblox. rbx.exe handles the rest — reading, aiming math, and streaming movements to the chip.
Having trouble? Unplug the device, hold BOOT, replug while holding, release — then hit Reset device on the flash screen or just replug.