Mokxi and Digital, the logic simulator, compared fairly
Mokxi is a free, browser-based alternative to Digital for logic lessons on machines that cannot install Java: gates, flip-flops, custom chips checked against truth tables, and a path from one NAND gate to a working computer. Digital, by Helmut Neemann, is a free, open-source logic designer and circuit simulator for teaching, a Java desktop program inspired by the original Logisim. Mokxi is a free circuit and firmware simulator in a browser tab, with a logic path of its own. Here is where each one is the right answer.
Last checked September 2026
- 228parts on the bench
- 31boards running now
- 1.00xreal time, on every board
The Mokxi editor running the Kestrel, a CPU of about four thousand NAND gates, with its program in ROM and a terminal beside it.
Where Digital leads
These are the strongest reasons to choose Digital today.
- Free and open source under the GPL-3.0, and it runs offline anywhere Java 8 or later runs.
- Test cases stored with the circuit, and analysis that derives a truth table and expressions from a circuit, including circuits with flip-flops.
- Components described in VHDL or Verilog, export to FPGA boards such as the BASYS3 and the TinyFPGA BX, and JEDEC files for GAL chips.
- A library of the common 74xx chips, a finite state machine editor, and a measurement graph of signals over time.
Where Mokxi leads
These are working parts of Mokxi you can open and test for yourself.
- Runs in a browser tab with nothing to install, so it works on a school Chromebook.
- A path from one NAND gate to a computer, lesson by lesson: package any circuit as a chip, check it against its truth table, and build up to the Kestrel CPU running a program from ROM.
- Real 74HC chips and a 555 on a 0.1 inch breadboard, and analog parts with bench instruments, beside the ideal gates.
- Microcontrollers on the same canvas: 31 boards run real compiled C++, and classes add starters, checks, submissions and a gradebook.
Side by side
Last checked September 2026. If anything here has gone stale, that is our mistake and we want to know.
| Mokxi | Digital | |
|---|---|---|
| Aimed at | Logic, breadboard circuits and firmware | Digital logic design and teaching |
| Runs in | A browser tab, including on Chromebooks | A Java desktop program |
| Price | Free; paid plans for classes and more room | Free and open source |
| Testing a circuit | Truth-table checks in each lesson, row by row | Test cases stored with the circuit |
| HDL and FPGA | No | VHDL and Verilog, with FPGA board export |
| Offline | Keeps running once the tab is open | Yes, as a desktop program |
Sources for Digital
Which one should you use
Straight answers. Where the other one is the right call, we say so.
You are heading for an FPGA, or teaching VHDL or Verilog
Digital.
You want test cases that travel with a circuit file
Digital. They are one of its core features.
Your students are on Chromebooks
Mokxi runs in the browser with nothing to install.
You want a guided path from one NAND gate to a computer, with a teacher checking the work
Mokxi.
Compare the other options
The same straight comparison for the tools teachers, students and makers also consider.
In short
Should I use Mokxi if you are heading for an fpga, or teaching vhdl or verilog?
Digital.
Should I use Mokxi if you want test cases that travel with a circuit file?
Digital. They are one of its core features.
Should I use Mokxi if your students are on chromebooks?
Mokxi runs in the browser with nothing to install.
Should I use Mokxi if you want a guided path from one nand gate to a computer, with a teacher checking the work?
Mokxi.
Try it yourself
A comparison page is somebody else’s opinion. Open the editor, press Run and make up your own mind.
Free forever. Every board and part. Saves your projects. Works on Chromebooks.