New Deltora v1.1 — All 8 tools live →

Solve Theory of
Computation.
Visually.

The complete interactive toolkit for CS students — DFA, NFA, Turing Machines, PDA, Pumping Lemma, Arden's Theorem and more. Step-by-step. Free.

Open Deltora → See all features
automatalab.app · DFA Builder
start q0 a q1 b q2 b q3 a,b ACCEPTED input: "abb"
DFA Builder NFA Simulator Subset Construction Mealy Machines Moore Machines Turing Machine Tape PDA Stack Visualizer Pumping Lemma Proof Arden's Theorem DFA Minimization Regex to NFA Pipeline Step-by-Step Proofs
8
Interactive Tools
3
Input Methods
100%
Free For Now
0
Login Required
Features

Everything you need to
master automata theory

Every tool built for clarity — not just correct answers, but the exact reasoning that leads to them.

DFA / NFA

Build automata three different ways

Click and drag states on a canvas, fill in a transition table, or type raw text notation. All three input modes produce the same live diagram — pick whatever fits how you think.

Canvas Table Text
# Text input mode
start: q0
accept: q2
q0,a->q1
q1,b->q2
q2,a->q0
✓ "ab" accepted at q2
Conversions

Convert between any machine type

NFA to DFA via subset construction. Mealy to Moore and back via state splitting. Every intermediate step shown — not just the result, but the full derivation table.

Try Converter
Subset Construction
Convert
DFA State a b
→ q0q0,q1q0
q0,q1q0,q1q0,q2 *
q0,q2 *q0,q1q0
Simulators

Watch machines execute, step by step

Turing Machine tape animation with frame-by-frame head movement. PDA stack visualization with every push and pop visible. Full configuration history — click any step to jump to it.

Try Simulators
Turing Machine — Step 4 of 9
X
X
a
b
b
B
▲ head at pos 2
State: q1 | Read: a
Proofs

Generate formal proofs, not just answers

Pumping Lemma solver walks through the full 7-step contradiction proof for any language. Arden's Theorem derives regular expressions from DFA state equations exactly as your textbook does.

Try Proof Solver
STEP 1 — Assume L is regular. By PL, ∃ p ≥ 1.
STEP 2 — Choose w = aᵖbᵖ ∈ L. |w| ≥ p. ✓
STEP 4 — Since |xy|≤p, y = aᵙ (k ≥ 1)
STEP 7 — L = {aⁿbⁿ} is NOT regular. QED. ∋
All Tools

Eight tools. One place.

No switching tabs, no installs, no login. Open the app and start solving immediately.

⬡
DFA / NFA Builder
Build and simulate deterministic and nondeterministic automata with full state trace.
⇄
NFA → DFA
Subset construction with epsilon-closure tracking shown step by step.
⇌
Mealy ↔ Moore
Convert between output-on-transition and output-on-state machines in both directions.
⊕
PDA Simulator
Pushdown automaton with visual stack and full clickable configuration history.
▤
Turing Machine
Animated tape with step-by-step head movement and live-editable rules.
∵
Pumping Lemma
Generate complete formal proofs for proving a language is not regular.
∵
Arden's Theorem
Solve DFA state equations to derive the equivalent regular expression.
⌘
Regex Pipeline
Thompson's NFA construction + subset DFA with full intermediate diagrams.
⊡
DFA Minimization
Table-filling (Myhill-Nerode) with distinguishability matrix and merge steps.
Get started

Stop memorizing.
Start understanding.

Open Deltora and solve your first automaton in under 60 seconds — no account, no install, no friction.

Open Deltora → View pricing