AutomataVerse.

Automata and formal languages are usually taught on paper, where a student cannot run a machine to see why it accepts or rejects a string, and a teacher has to trace every submission by hand.

AutomataVerse lets you draw any of seven machine types (DFA, NFA, DPDA, NPDA, Turing machine, Mealy, Moore) on a canvas, then step through an input with the active states, tape and stack shown as it goes.

Conversions such as NFA to DFA, minimization and regex to NFA play step by step, and teachers can run classrooms with auto-graded assignments. Building and simulating needs no install and no account.