Live at velxio.dev

Velxio is an open-source, browser-based emulator for Arduino and embedded development boards. Write Arduino C++ or Python, compile it, and simulate it with real CPU emulation and 48+ interactive electronic components — without installing a toolchain, without flashing hardware, and without leaving the browser.

• Run real CPU emulation across 19 boards and 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).
• Wire up 48+ interactive components — LEDs, buttons, sensors, OLED/TFT displays, motors, NeoPixels — and watch the simulation update in real time.
• Compile sketches via arduino-cli in the backend, with a full multi-file workspace, library manager, and Serial Monitor.
• Mix architectures on the same canvas — for example, an Arduino Uno talking to a Raspberry Pi 3 over serial.
• Save projects, share public URLs, or self-host the entire stack with a single Docker command.

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

Then open http://localhost:3080.

Velxio is open-core and dual-licensed. Choose the license that matches how you intend to use it.

The Velxio source code is published under the GNU Affero General Public License v3.0. You are free to use, modify, redistribute, and self-host Velxio at no cost — including for commercial purposes — as long as you comply with the AGPLv3 copyleft terms: any modifications or derivative works you distribute, or that you make available to users over a network, must also be released under AGPLv3 with full source code.

This is the right license for:

• Personal projects, learning, and research
• Open-source projects already released under AGPLv3
• Self-hosted deployments where you are willing to share your modifications

Full text: LICENSE.

If AGPLv3 does not fit your use case — for example, you want to embed Velxio in a closed-source product, run it as a SaaS without publishing your modifications, or rebrand it for clients — a Commercial License is available.

The Commercial License grants you:

• The right to use, modify, and distribute Velxio as part of a proprietary product
• Exemption from the AGPLv3 network-copyleft clause — you do not have to release your source code
• Permission to keep modifications private
• Email support (tier-dependent)

You need a Commercial License if you intend to:

• Run Velxio as a closed-source SaaS or web application
• Embed Velxio in a commercial closed-source desktop or embedded product
• Use it as an internal corporate tool without sharing source with users
• White-label or rebrand Velxio for resale

Indicative tiers (Startup / Business / Enterprise); pricing is negotiated per project, with volume discounts and perpetual options available. Full terms: COMMERCIAL_LICENSE.md.

To request a quote, email davidmonterocrespo24@gmail.com with a brief description of your use case and expected developer headcount.

To preserve the dual-licensing model, external contributors are asked to sign a Contributor License Agreement (CLA) before pull requests are merged. The CLA assigns joint copyright to the project maintainer so the dual-license remains valid; contributors retain their own copyright.

velxio.dev is the official hosted instance. It runs the same open-source code from davidmonterocrespo24/velxio plus a small private analytics overlay used to understand product usage. The open-source app stays AGPLv3 and remains the canonical, fully usable version — there is no feature gating between the OSS Docker image and the hosted site.

Velxio is built and maintained by David Montero Crespo. If the project saves you time, sponsorship helps cover server costs and frees up time for new boards, components, and features.

• Email: davidmonterocrespo24@gmail.com
• GitHub: @davidmonterocrespo24
• Discord: Join the community

Copyright (C) 2025 David Montero Crespo