Simulator

ESP32 DevKit simulator, running in this tab

Mokxi is a free ESP32 DevKit simulator that runs in your browser, with nothing to install and no account needed. The classic ESP32, not the RISC-V ones: Mokxi models the thirty-pin DOIT DevKit V1 with its Xtensa LX6 at 240 MHz, the GPIO matrix, UART0, a twelve-bit ADC1 and the LEDC PWM controller, on our own Xtensa core. Wire the circuit, press Run.

  • 505parts on the bench
  • 45boards running now
  • 1.00xreal time, on every board
ESP32 DevKit: blinklive0.000 s 0.00x
Click to open it in the editor
Real firmware, running right now on our own core. Click it to open the circuit in the editor.
What is modeled

The numbers, not the marketing

Taken from the board's own contract document and put in plain words.

The coreXtensa LX6 in the windowed ABI, one instruction per cycle at 240 MHz. One core, not the chip’s two.
Six pins that cannot be outputsGPIO 34 to 39 have an input buffer and no output driver at all. A pinMode(34, OUTPUT) is refused here the way it is refused on silicon, and the board shows an amber mark rather than letting you believe otherwise.
What is not thereNo radio, no second core, no FPU, no cache or flash. Your own sketch compiles in the tab. WiFi is simulated: the Arduino API over a network of ours, with no 802.11 behind it, and real internet when you sign in and switch it on.
Go further

The full board page

Every peripheral area, every example and the wiring notes, in one place.

ESP32 DevKit simulatorBlink, a button and the serial monitor, running.
How it works

Three steps from a blank tab to a running circuit.

  1. Open the editor

    It runs in your browser tab. Nothing to install, and you need no account to start.

    Your first project
  2. Wire it and write the code

    Drag parts onto a breadboard, run each wire from pin to pin, and write the sketch beside it.

    Wiring
  3. Press Run

    Your sketch compiles in the tab and runs on a model of the chip, with the Serial Monitor beside it.

    Run and serial
Reviews

What makers say about Mokxi.

“The AI checker helps check and correct my circuits, and it has way more components than Tinkercad. As a student I really appreciate the tool.”

ChloeEngineering student

“I’d been looking for a real online electronic simulator that was intuitive and complete when I found Mokxi. I was able to quickly import a Fritzing file and my Arduino sketch and start testing. Mokxi has all of the makings for the best online Arduino simulator I have been able to find!”

JayModel builderFeatured in his DioramaOS post

“I’m using Mokxi to develop and simulate an STM32-based four-wheel-drive robot car before building the actual hardware. It allows me to experiment with DC motor control, PWM, RPM measurement using photointerrupters, and different acceleration, braking, and reversing strategies, helping me understand and refine the system before implementing it in real life.”

NusretRobot car builder, Hamburg

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FAQ

Questions, answered.

Is it free?

Yes, with no card and no account needed to try it.

Which ESP32 is this?

The classic Xtensa one: an ESP32-WROOM-32 on the thirty-pin DOIT DevKit V1. The ESP32-C3 and ESP32-C6 here are the RISC-V parts and have their own pages.

Can I compile my own sketch?

Yes. Edit the sketch and press Run: it compiles in the tab with clang for Xtensa, and the build panel shows every step. Nothing is uploaded.

Does it simulate WiFi or Bluetooth?

Both, simulated, and it says so: WiFi is the Arduino API over a network of ours, and Bluetooth is a phone in the editor’s Bluetooth pane. There is no radio and no 802.11 behind either, and signed in you can switch on real internet.

Can I use analogRead and analogWrite?

Yes. analogRead is ADC1 on GPIO 36, 39, 32, 33, 34 and 35, twelve bits of the real net voltage, and at the default attenuation it follows a real part’s curve, reaching 4095 at about 3.1 V, so a 3.3 V pot gets to 4095 a little before the end of its travel. analogWrite is LEDC on any pin with an output driver, and it costs the core nothing.

Simulators for one kind of circuit

A servo, a display, a motor driver or a rectifier, each already running.

Try your own firmware on the ESP32 DevKit

What you build here runs on the board on your desk, unchanged. Nothing to install and no account needed.