Velxio 2.0 – Emulate Arduino, ESP32, and Raspberry Pi 3 in the Browser

Live at velxio.dev

A fully local, open-source multi-board emulator. Write Arduino C++ or Python, compile it, and simulate it with real CPU emulation and 48+ interactive electronic components — all running in your browser.

19 boards · 5 CPU architectures: AVR8 (ATmega / ATtiny), ARM Cortex-M0+ (RP2040), RISC-V RV32IMC/EC (ESP32-C3 / CH32V003), Xtensa LX6/LX7 (ESP32 / ESP32-S3 via QEMU), and ARM Cortex-A53 (Raspberry Pi 3 Linux via QEMU).

Velxio is free and open-source. Building and maintaining a full multi-board emulator takes a lot of time — if it saves you time or you enjoy the project, sponsoring me directly helps keep development going.

Your support helps cover server costs, library maintenance, and frees up time to add new boards, components, and features. Thank you!

https://velxio.dev — no installation needed. Open the editor, write your sketch, and simulate directly in the browser.

To self-host with Docker (single command):

docker run -d -p 3080:80 ghcr.io/davidmonterocrespo24/velxio:master

Then open http://localhost:3080.

Key Features

Monaco Editor— Full C++ / Python editor with syntax highlighting, autocomplete, minimap, and dark theme. Multi-file workspace— create, rename, delete, and switch between multiple .ino, .h, .cpp, and .py files. Arduino compilation via arduino-cli backend — compile sketches to .hex / .bin files. Compilation console— resizable output panel showing full compiler output, warnings, and errors.

Hardware Emulation

AVR8 Emulation: Real ATmega328p / ATmega2560 / ATmega32u4 / ATtiny85 emulation at native clock speed. Full GPIO, Timers, USART, ADC, SPI, and I2C support.

RP2040 Emulation: Real RP2040 emulation at 133 MHz via rp2040js. Supports all 30 GPIO pins, ADC, I2C, SPI, and PWM. Includes an Oscilloscope for signal analysis.

ESP32 Emulation: Real Xtensa LX6/LX7 dual-core emulation via QEMU. Supports GPIO, UART, ADC, I2C, SPI, RMT/NeoPixel, and WiFi (SLIRP NAT).

RISC-V Emulation: RV32IMC emulation in TypeScript for ESP32-C3 and CH32V003. Instant startup and works offline.

Raspberry Pi 3B: Full BCM2837 emulation via QEMU. Boots real Raspberry Pi OS and runs Python scripts with GPIO interaction.

Components and UI

• 48 electronic components from wokwi-elements.
• Component picker with search, category filters, and live previews.
• Drag-and-drop repositioning and 90° rotation.
• Interactive Wiring: Orthogonal routing with 8 signal-type wire colors (VCC, GND, Analog, Digital, etc.).