Introduction

QuantumJS is a modern, expressive Quantum Circuit Domain Specific Language (DSL) and AST-driven compiler for JavaScript and TypeScript.

It lets you describe quantum circuits using a fluent, chainable API — then compile them to OpenQASM 3.0 (with OpenQASM 2.0 compatibility) for execution on real quantum processors or local statevector simulators.

Why QuantumJS?

Writing quantum circuits in raw QASM is verbose and error-prone. QuantumJS gives you:

• Fluent chaining — compose gates naturally: Q.bit(0).h().cx(Q.bit(1))
• Expressive inputs — initialize state from binary strings, Pauli strings, or gate arrays
• Scoped staircase loops — growUp, growDown, shrinkUp, shrinkDown for elegant recursive patterns like QFT
• Pipeline abstraction — wrap input prep, algorithm, and output measurement into a single structured job
• Dual QASM output — target OpenQASM 3.0 by default or 2.0 for legacy compatibility
• Custom routines — extend the DSL with reusable, chainable functions

Live Demo

An interactive IDE to write, visualize, and simulate circuits is available at quantumjs.netlify.app.

Installation

npm install @quantum-js/dsl
# or
bun add @quantum-js/dsl

Quick Example

import { circuit } from '@quantum-js/dsl';

const c = circuit({ qubits: 2 }, Q => {
  Q.bit(0).h();
  Q.bit(0).cx(Q.bit(1));
  Q.all().measure();
});

console.log(c.compile()); // OpenQASM 3.0

Output:

OPENQASM 3.0;
include "stdgates.inc";
qubit[2] q;
bit[1] c;
h q[0];
cx q[0], q[1];
c = measure q;

Package Structure

QuantumJS is organized as a monorepo:

Package / App	Description
packages/quantumjs	Core DSL, AST, and compiler
apps/bench	Interactive live IDE and circuit visualizer
apps/documentation	This documentation site