7 machine types · free

Build the machine.
Watch it read.

A visual simulator for automata theory. Draw states and transitions, feed in a string, and step through the computation one symbol at a time — DFA, NFA, PDA, Turing machines, Mealy and Moore.

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Open it

Step

One symbol at a time

Step through a run or let it play to the end. The active state and the symbol under the head move together.

Draw

Controls where you look

Select a state and its controls appear beside it. Nothing permanent covers the diagram.

Teach

Classrooms and grading

Set a problem, students submit a machine, you grade it with a score and written feedback.

Keep

Yours to export

Machines stay in your browser by default. Export as JSON or PNG whenever you want.

Eight worked examples, one click away

Load a machine, run a string, then edit it into your own.