Simulator

ESP32-S3 simulator, running in this tab

Mokxi is a free ESP32-S3 simulator that runs in your browser, with nothing to install and no account needed. The ESP32-S3, on our own Xtensa core: Mokxi models the ESP32-S3-DevKitC-1 with its LX7 at 240 MHz, the GPIO matrix, UART0 and the chip’s own USB serial port, a twelve-bit ADC1, LEDC PWM and the RMT that drives the board’s RGB LED. Wire the circuit, press Run.

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ESP32-S3: 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 LX7 in the windowed ABI, one instruction per cycle at 240 MHz. One core, not the chip’s two.
An RGB LED, not a plain oneLED_BUILTIN on this board is an addressable LED on GPIO48 (GPIO38 on v1.1). digitalWrite on it sends a WS2812 frame through the RMT peripheral, and the LED on the board lights with the color the frame carries.
PinsGPIO 0 to 48 through the GPIO matrix and the IO MUX, with the reset pulls from Espressif’s manual on every pad. GPIO 26 to 32 are the flash. analogRead is ADC1 on GPIO 1 to 10, with the four attenuations.
Serial, PWM and timeUART0 at the configured baud rate and the USB Serial/JTAG port, 64 bytes a packet; the serial monitor hears both. LEDC has eight channels and four timers behind analogWrite, ledcAttach and ledcWrite. SYSTIMER unit 0 at 16 MHz is behind millis() and micros().
What is not thereNo radio, no second core, no FPU, no cache, flash or PSRAM. 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-S3 simulatorBlink, a button and the serial monitor, running.
Guides

Step-by-step guides for the ESP32-S3

Each one has the parts, the wiring and the code, and ends in a circuit you can run.

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 ESP32-S3, the dual-core Xtensa LX7 part, on Espressif’s own ESP32-S3-DevKitC-1. The classic ESP32, the C3 and the C6 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 1 to 10, twelve bits of the real net voltage. analogWrite is LEDC on any pin, 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-S3

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