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Design and run IoT circuits in the browser

A wiring canvas, a code editor, an Arduino interpreter and a serial monitor in one app. ESP8266, ESP32 and Arduino Uno — no hardware required.

3 board ESP8266 ESP32 Arduino Uno

Open Simulator Download the desktop app
ESP8266 PWR LED SERVO BUZZER
Fig. 00 Live schematic ESP8266 · LED · servo · buzzer — the animation traces signal moving along each wire.
CircuitLab — Arduino & IoT Circuit Simulator
Boards 3 ESP8266 NodeMCU V3, ESP32, Arduino Uno
Components 40 microcontrollers, input, output, passive
Libraries 22 emulated inside the interpreter
Platforms 3 web, macOS, Windows

Inside the app

The four panels you spend the most time in while wiring, writing and running a sketch.

Editor and canvas on one screen
Fig. 01 Editor and canvas on one screen
Arduino code editor with autocomplete
Fig. 02 Arduino code editor with autocomplete
Wiring canvas and wire routing
Fig. 03 Wiring canvas and wire routing
Schematic view
Fig. 04 Schematic view

Everything you need to learn and prototype

From wiring a circuit to reading simulation output, it all happens in one app.

Visual wiring canvas
Drag components, connect pins, and route wires. Wire colors, direction labels, and a View/Edit mode keep things tidy.
Arduino interpreter
Runs a subset of Arduino C++: setup/loop, data types, control flow, functions, arrays, and library objects — right in the browser.
Code editor
Monaco Editor with Arduino highlighting, context-aware autocomplete, error markers, and multi-file projects.
Serial Monitor, Plotter & Oscilloscope
Watch Serial output, plot sensor values, and inspect digital/PWM pin levels in a full-width bottom panel.
Virtual web console
Test WebServer sketches: list routes, send requests, and read responses — with no real network.
Full board & component set
ESP8266/ESP32/Uno plus temperature, gas, motion, RFID and ultrasonic sensors, displays, servos, motors and more.
Environment simulation
Virtual objects move, so distance, motion, temperature and humidity change on their own — sensors react by themselves.
Desktop app
The desktop build runs offline and flashes firmware to real ESP32/ESP8266 hardware.

Download the desktop app

The desktop build runs offline and supports flashing firmware to hardware.

Latest version · v0.5.0 · Sep 17, 2026

Builds are not code-signed yet, so macOS Gatekeeper / Windows SmartScreen may warn you during installation.

Build your first circuit

The simulator runs in your browser. No install, no account.

Open Simulator