Source: https://mokxi.com/online-circuit-simulator Updated: 2026-09-27 Your electronics workbench, online # Build a working circuit before your parts arrive. Mokxi is a free online circuit simulator that runs in your browser. Wire a breadboard, write real microcontroller code and press Run. See the LEDs, signals, serial output and scope traces change in front of you, with nothing to install. Try it now, no account Sign up free No card. No download. The simulator stays free. Real ESP32-C3 firmware running now. Open it, play it and change the code. Runs in your browser Start in seconds Real code Compiled in the tab Free simulator No card required Made for class Teacher and student tools From idea to answer ## Three steps. The circuit tells you what happens. You learn by changing the real thing, not by watching somebody else do it. 1 ### Wire it Choose a board, drop parts onto the breadboard and drag wires between real pins and holes. 2 ### Code it Edit the sketch beside the circuit. Mokxi compiles it in your browser for the board you chose. 3 ### Run it Press Run, use the buttons, read Serial and inspect signals with the plotter and scope. One bench, different goals ## Start where you are. The same project can be a first lesson, a class submission or a prototype you keep improving. ### Students Understand what each wire and line of code changes. - Begin with a working project - Break it safely and try again - Share the result with one link Start learning ### Teachers Give the whole room a clear path from starter to submission. - Assign one starter circuit - Watch class progress - Check work consistently See Classroom ### Makers Test the idea while the parts are still in the mail. - Use real board pinouts - Keep project history - Move the sketch to hardware Open the workbench What is inside ## A full lab around the circuit. The tools stay together, so there is no copy and paste between a drawing app, an editor and a serial terminal. ✓ ### Breadboard and boards Real holes, nets, pins and power rails, with Arduino, ESP32, Raspberry Pi Pico, STM32, micro:bit and more. ✓ ### Code that runs Write the sketch in the built-in editor, compile it for the selected board and run its firmware against the circuit. ✓ ### Instruments beside it Serial monitor, plotter, scope, measurements and notes stay attached to the work you are testing. ✓ ### Work you can keep Save private projects, share a link, export an image and return to earlier versions when an experiment goes wrong. For a room full of learners ## Teach the circuit, then see who understood it. The Teacher plan keeps setup, progress, submissions and support in the same place as the simulator. ✓ ### Start together Give every student the same starter project instead of rebuilding it desk by desk. ✓ ### Keep students moving Use the roster and teacher dashboard to find who is working and who needs help. ✓ ### Check the result Write assignment checks once and apply the same standard to every submission. ✓ ### Buy it like a school One flat price for a teacher, or a written quote for a whole school, paid by purchase order. Teacher $129 a year, 40 student seats included You plus 40 students, across as many classes as you like. More than forty, several teachers, or a whole school? We price it for you. Plan a class Ask us about your school Start free, move up with a reason ## The simulator is not held behind a payment. Paid plans add room, collaboration and classroom control. Your circuits still run on Free. ### Free $0 forever The whole simulator, for anyone, forever. - Live collaboration: you and one other person - Every board and part - Compiled in your browser - 10 saved projects Start free ### Pro popular $100 a year For the person who lives in the editor. - Live collaboration: rooms of up to 5 people - Unlimited classes, 10 students - Unlimited projects - 200 saves of history each Choose Pro ### Teacher $129 a year You plus 40 students, in any classes, one flat price. - 40 student seats included: as many classes as you like - Live collaboration: the whole class, one project - Everything in Pro, for you - Pro’s room for every student Choose Teacher ### Schools & universities Custom Over 40 students, several teachers, a school, district or university. - Class collaboration: the whole room, one project - A quote for each teacher - Purchase orders, net-30 - Data privacy agreement signed Talk to us Compare every feature and billing option → Before you start ## Straight answers No download, no card for Free, and no hidden step before the circuit runs. Is Mokxi really free? Yes. The simulator, boards, parts, code compiler, serial monitor and sharing all work on the Free plan. No card is required. Paid plans add collaboration, more cloud history and classroom tools. Do I have to install anything? No. Mokxi runs in the browser. Open it on a computer, tablet or phone and your circuit runs there. Can students use it without an account? Yes. A student can open the editor and run a circuit immediately. An account is used to save work to the cloud, join a class and submit assignments. Does the code transfer to real hardware? Mokxi compiles the sketch in the browser and models the board, pins and connected circuit. It is made for learning and prototyping. Always verify safety-critical and production designs on the real hardware. What does a teacher get? The Teacher plan adds 40 student seats, rosters, assignments with checks, a teacher dashboard and whole-class collaboration, paid by card or purchase order. A school with more students or several teachers gets a written quote. ## Build your first working circuit now Start free, keep the whole simulator, and move up only when collaboration or classroom tools earn their place. Try it now, no account Sign up free