FreeOCD
Free On-Chip Debugger

Open-source debugging for ARM Cortex-M,
from your browser and your editor.

FreeOCD is a modern, fully open-source toolchain for flashing, verifying, and RTT-debugging ARM microcontrollers over CMSIS-DAP — in the browser via WebUSB, and inside VS Code with first-class MCP support for AI agents.

Projects

Everything FreeOCD ships, in one place.

FreeOCD WebDebugger

Web · WebUSB

A browser-based open-source debugger for ARM Cortex-M microcontrollers. Flash and interact with your target over WebUSB + CMSIS-DAP — no installation required.