StAX-XML - High-Performance JavaScript XML Parser Library

New in v1.1: Read → Modify → Write

writeEvent() connects EventReader and EventReaderSync directly to every writer. XML declaration metadata, namespace declarations, attributes, and self-closing syntax stay available while your code replaces only the events it needs. For allocation-sensitive transformations, pair a StreamReader with the writer’s individual stream methods instead.

Build an XML transformation pipeline →

Why Choose StAX-XML for JavaScript XML Parsing?

🚀 High-Performance XML Processing

Benchmarked XML parser optimized for speed and memory efficiency. Outperforms traditional DOM parsers for large XML files. See Performance Benchmarks

🔄 Streaming XML Parser

Memory-efficient parsing and read-modify-write pipelines. Process XML files of any size without loading the entire document. Learn Streaming API

🌐 Browser and Runtime Compatibility

Works in Node.js, Bun, Deno, and modern browsers through the same pure JavaScript parser core. Installation Guide

📝 TypeScript-First XML Parser

Built with TypeScript, providing comprehensive type definitions and IntelliSense support. Full type safety for XML parsing operations. TypeScript Examples

JavaScript XML Parser Installation

Choose your preferred package manager to install StAX-XML:

# npm - Most popular package manager
npm install stax-xml

# yarn - Fast, reliable package manager
yarn add stax-xml

# pnpm - Efficient disk space usage
pnpm add stax-xml

# bun - Ultra-fast JavaScript runtime
bun add stax-xml

# deno - Secure TypeScript runtime
deno add npm:stax-xml

ESM-only package: StAX-XML is published as ESM-only. Use import { ... } from 'stax-xml'; require('stax-xml') is not supported.

Platform Requirements:

• Node.js 20.19+
• Modern browsers (ES2020+)
• TypeScript 4.5+ (optional)

→ Complete Installation Guide

XML Parser Quick Start Example

Get started with StAX-XML in seconds. Here’s how to parse XML with streaming support:

import { EventReader, XmlEventType } from 'stax-xml';

// XML content to parse
const xmlContent = '<bookstore><book id="1"><title>JavaScript Guide</title></book></bookstore>';

// Create ReadableStream for streaming XML parsing
const stream = new ReadableStream({
  start(controller) {
    controller.enqueue(new TextEncoder().encode(xmlContent));
    controller.close();
  }
});

// Parse XML asynchronously with event-driven approach
async function parseXml() {
  const parser = new EventReader(stream);
  for await (const event of parser) {
    if (event.type === XmlEventType.START_ELEMENT) {
      console.log(`Found element: ${event.name}`);
    }
  }
}
parseXml();

→ More Advanced Examples | → API Documentation

StAX-XML vs Other JavaScript XML Parsers

Unlike traditional XML-to-JSON mappers, StAX-XML provides pull-based parsing that gives you complete control over XML processing:

Key Advantages:

• 🔥 Memory Efficient: Stream large XML files without loading them entirely into memory
• ⚡ High Performance: Faster than DOM-based parsers for large XML documents
• 🎯 Flexible Mapping: Transform XML to any custom data structure, not just JSON
• 🌍 Runtime Support: Works in Node.js, Bun, Deno, and modern browsers
• 📘 TypeScript Ready: Complete type definitions for enhanced developer experience
• 🔧 Namespace Aware: Proper XML namespace handling and entity decoding

Popular Use Cases:

• Large XML File Processing: RSS feeds, XML data exports, configuration files
• Real-time XML Streaming: Live data feeds, server-sent events
• Memory-Constrained Environments: Edge computing, serverless functions
• Custom XML Transformations: Data migration, format conversion

→ Performance Benchmarks | → Frequently Asked Questions