March 9, 2026
Let the blink wars begin
Velxio, Arduino Emulator
Arduino in your browser — free, offline, and the Wokwi showdown begins
TLDR: Velxio is a free browser-based Arduino simulator that runs locally with no accounts and supports Arduino Uno and Raspberry Pi Pico. Fans are thrilled, while a side debate compares it to Wokwi, pitting offline control and self-hosting vibes against sticking with a popular, hassle-free online option.
Velxio just dropped a crowd-pleaser: a free, open-source way to build gadget projects right in your browser, no signup and no cloud. It simulates real Arduino boards (think the classic Uno and the teeny Raspberry Pi Pico), lets you drag 48+ virtual parts like LEDs and buttons, and even compiles code into real files you could put on hardware. The vibe in the comments? Pure hype. One fan yelled “This is amazing!”, another said they “can’t wait to play,” and the creator tossed in the internet’s favorite rite of passage: a blinking LED code snippet with chatty serial messages. It’s giving cozy weekend project energy.
But because it’s the internet, comparison season arrived fast. A commenter dropped a link to Wokwi — the big name in online microcontroller simulators — noting it also runs Arduino (and ESP32). Cue the friendly face-off: Team Local loves that Velxio runs fully on your own machine and can be self-hosted “with one command,” while Team Why Switch wonders if sticking with the proven online tool is simpler. No pitchforks, just playful “blink-offs” and bragging rights about offline control versus easy web life. Meanwhile, tinkerers cracked jokes about finally “blowing up” LEDs safely on a screen and spamming “LED ON / LED OFF” in the Serial Monitor until the cat complains. The mood? Nerdy, noisy, and wildly enthusiastic, with a side of simulator soap opera.
Key Points
- •Velxio is a free, open-source, browser-based Arduino emulator that runs locally without cloud or accounts.
- •It emulates AVR8 (ATmega328p) via avr8js and RP2040 via rp2040js, supporting Arduino Uno and Raspberry Pi Pico boards.
- •The platform integrates Monaco Editor, a Serial Monitor, a Library Manager, and supports multi-file Arduino projects.
- •Compilation uses arduino-cli to produce real .hex and .uf2 firmware files; interfaces like I2C, SPI, USART, ADC, PWM are supported.
- •Velxio can be self-hosted with a Docker image; licensed under GNU AGPLv3 with a commercial option for proprietary use.