Regex Visualizer
Visualize a regex as a Thompson NFA state machine graph. See states, transitions, and epsilon moves. Free online — runs locally, no upload.
Supports: literals, . (any), * / + / ? quantifiers, | alternation, () groups, [a-z] char classes, ^ / $ anchors.
Enter a regex pattern to visualize its NFA state machine
Start state
Accept state (double circle)
Char transition
ε (epsilon — empty)
0
States
0
Transitions
0
Epsilon moves
0
Char moves
Built using Thompson's construction — converts a regex into a nondeterministic finite automaton (NFA). Each circle is a state; arrows show transitions on input characters or epsilon (empty) moves.