When Developers Need JSON ↔ XML Conversion
JSON and XML serve different parts of the software ecosystem. Most modern REST APIs speak JSON. But enterprise systems — especially in banking, insurance, healthcare, and government — still use XML and SOAP extensively. If you work in integration, middleware, or enterprise software, you'll encounter the need to convert between them regularly.
The Browser Tool Use Case
HarborConvert's JSON/XML converters are useful for:
- Debugging: Quickly inspect an API response in the other format
- Prototyping: Transform sample data without writing a script
- One-off transformations: Small data files that don't justify a pipeline
- Testing: Generate test fixtures in the format your system expects
For production pipelines, you'll want a programmatic solution (see below). For everything else, a browser-based tool is faster.
Mapping Rules
JSON to XML
| JSON | XML |
|---|---|
Object {} | Element with child elements |
Array [] | Repeated elements with same tag name |
| String/Number/Boolean | Element text content |
null | Empty element |
| Key name | Element tag name |
Note: JSON keys can contain characters that are invalid in XML element names (spaces, hyphens, leading numbers). The converter handles these by replacing invalid characters, but you may want to pre-clean your keys.
XML to JSON
XML has concepts JSON doesn't: attributes, namespaces, mixed content (text and elements at the same level), comments, and processing instructions. Conversion decisions:
- Attributes →
@attributeskey - Namespaces → preserved as-is in element names, or stripped
- Comments → dropped
- Mixed content → may lose structure
Browser Use: Step-by-Step
JSON → XML: Go to json-to-xml, paste or upload your JSON, download XML.
XML → JSON: Go to xml-to-json, paste or upload your XML, download JSON.
Programmatic Options
For production use:
Node.js: xml-js library (the same one powering HarborConvert's converter)
npm install xml-js
import { xml2json, json2xml } from 'xml-js';
const json = xml2json(xmlString, { compact: true, spaces: 2 });
Python: xmltodict for XML→JSON, dicttoxml for JSON→XML
Java: Jackson's XML module (jackson-dataformat-xml)
Edge Cases to Watch
- Root element requirement: XML must have a single root element. If your JSON is an array at the top level, the converter wraps it in a
<root>element. - Type information: JSON has typed numbers and booleans; XML text is always a string. Round-tripping loses type information.
- Large files: Browser conversion works fine for files up to a few MB. For multi-gigabyte XML transforms, use streaming command-line tools (xmlstarlet, jq with a wrapper).