XQDB

A high-performance connector to kdb+/q with Python (Narwhals/Arrow) and Node.js (TypeScript) bindings.

XQDB is independent and not affiliated with or endorsed by KX. kdb+ is a trademark of KX.

Overview

XQDB provides high-performance connectivity between Python and Node.js applications and kdb+/q processes. The core is written in Rust, with Python bindings built on PyO3, Narwhals, and the Arrow C Stream interface, plus Node.js bindings built on napi-rs.

Features

• Synchronous and asynchronous queries to kdb+/q
• Full kdb+ IPC protocol v6 support
• Backend-independent eager DataFrame and Series exchange through the Arrow C Stream interface
• TLS encryption and authentication
• Automatic retry with exponential backoff
• Subscription support for real-time data
• Read q binary table files directly into DataFrames
• Serialize data as kdb+ IPC bytes without a connection

Project Structure

Directory	Description
crates/xqdb	Core Rust library (connector, IPC serde)
py-xqdb	Python bindings (PyO3 + Narwhals)
js-xqdb	Node.js and TypeScript package
bindings/napi-xqdb	Shared napi-rs native binding layer

Installation

Python

Requirements: Python ≥ 3.10, Narwhals ≥ 2.10, PyArrow ≥ 20.0.0; pandas and Polars are optional backend packages

Install from the repository root. The standard setuptools backend compiles the PyO3 extension through setuptools-rust:

python -m pip install .

Or for development:

python -m pip install -e .

Node.js

Requirements: Node.js ≥ 20

Install from source:

cd js-xqdb
npm install
npm run build

Quick Start

Python

import narwhals as nw
import xqdb

# Query with PyArrow backend (default)
conn = xqdb.Q("localhost", 1800, backend="pyarrow")

# Query
result = conn.sync("select from trade where date=last date")

# Extract native DataFrame: PyArrow, pandas, or Polars
df = nw.to_native(result)

# Send data (Narwhals or native eager DataFrame)
conn.sync("upsert", "table", df)

conn.disconnect()

Node.js

import { Q } from "xqdb";

const conn = await Q.connect({
  host: "localhost",
  port: 1800,
});

try {
  const result = await conn.sync("select from trade where date=last date");
  await conn.asyn("upsert", "table", ["AAPL", 10n]);
  console.log(result);
} finally {
  await conn.disconnect();
}

Documentation

• Python API Reference — Comprehensive API documentation and type mapping for Python/Narwhals bindings
• Node.js API Reference — Comprehensive API documentation and value mapping for Node.js/TypeScript bindings

License

XQDB is licensed under the BSD-3-Clause permissive open-source license, which permits use in proprietary and commercial applications.