Compo — the quantum composer
that literally falls into your hands
Drag & drop gates, tweak angles, edit OpenQASM 3.0 live, and see the results — instantly.
Build, simulate and visualize small quantum circuits — no PhD required.
Sign up for any of our quantum computing courses and get full access to Compo.
What is Compo?
A fast, friendly playground for learning and prototyping quantum circuits.
Compo is a fast, friendly playground for learning and prototyping quantum circuits. Drag gates onto a 1–4 qubit canvas, add controls with a click, and tune rotation angles with a slider.
The right panel shows clean, standards-compliant OpenQASM 3.0 that you can edit directly — Compo will reflect your code in the circuit and vice versa.
Run simulations locally with Qiskit Aer and get instant probability bars plus a live Bloch sphere visualizing q[0].
It's simple, visual, and made for experimentation.
Key Features
Everything you need to start building quantum circuits today.
Drag & Drop Gates
Intuitive interface — just drag quantum gates onto your circuit canvas. No coding required to start.
Live OpenQASM 3.0
See and edit standards-compliant OpenQASM code in real-time. Circuit and code stay perfectly in sync.
Instant Simulation
Run simulations locally with Qiskit Aer. Get probability distributions and results immediately.
Bloch Sphere
Live visualization of q[0] state on the Bloch sphere. See quantum states evolve as you build.
Rotation Controls
Fine-tune rotation angles with intuitive sliders. Perfect for experimenting with parameterized gates.
Add Controls Easily
Turn any gate into a controlled gate with a single click. Build complex multi-qubit operations fast.
Ready to Build?
Enroll in one of our quantum computing courses and get full access to Compo — the perfect companion for hands-on learning.
Explore Courses & Get CompoFrequently Asked Questions
Everything you need to know about Compo.
What is Compo?
Compo is a free, browser-based quantum circuit composer that lets you build, simulate, and visualize quantum circuits. It features drag-and-drop gates, live OpenQASM 3.0 editing, and instant simulation with Qiskit Aer.
Do I need to install anything to use Compo?
No installation required. Compo runs entirely in your web browser. Just click "Launch Compo" and start building quantum circuits immediately.
What is OpenQASM 3.0?
OpenQASM 3.0 is the Open Quantum Assembly Language, a standard for describing quantum circuits. Compo generates clean, standards-compliant OpenQASM 3.0 code that you can export and use with other quantum computing platforms.
How many qubits can I simulate in Compo?
Compo supports 1 to 4 qubits, making it ideal for learning quantum computing fundamentals and prototyping small circuits without requiring significant computational resources.
What is the Bloch sphere visualization?
The Bloch sphere is a geometric representation of a qubit's quantum state. Compo displays a live Bloch sphere for q[0], helping you visualize how quantum gates transform qubit states in real-time.
Is Compo free to use?
Yes, Compo is completely free. It's provided by Avenue78 as an educational tool to help people learn and experiment with quantum computing.
Want to Go Deeper?
Compo is perfect for practicing what you learn in our quantum computing courses.