Finite State Machine

Build and run finite state machines — define states, transitions, and test input strings.

Category: Algorithms · v1.0.0
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About This Simulator

Design your own finite state machine interactively. Add states, define transitions between them, mark accept states, and then feed input strings to watch the machine process them character by character. The current state highlights in real time as each input symbol is consumed. Great for understanding regular languages, parsers, and state-based logic.

How It Works

  1. Load a preset FSM or build your own
  2. Enter an input string in the text field
  3. Click Run to watch the FSM process the input step by step
  4. Green states are accept states — if the machine ends there, input is accepted
  5. Click Step to advance one character at a time
  6. Try different inputs to see which strings the machine accepts