How to use JSON ↔ XML Converter
The JSON ↔ XML Converter transforms JSON data to well-formed XML and XML documents back to JSON with a single click. It uses fast-xml-parser for accurate bidirectional conversion, handles attributes and nested structures, reports parse errors with context, and formats the output with clean indentation. Conversion runs entirely in your browser — your data is never uploaded.
- Choose the conversion direction: JSON → XML or XML → JSON.
- Paste your JSON object or XML document into the input field.
- Click Convert to transform the data into the target format.
- If there is a syntax error, an inline message shows the problem location.
- Copy the formatted output using the Copy button.
Your data never leaves your device — 100% private processing.
Structural differences between JSON and XML
JSON and XML represent the same data but with different philosophies. JSON is terse: objects use {}, arrays use [], and values are unquoted booleans/numbers or quoted strings. XML is verbose and self-describing: every value is wrapped in named tags, and metadata is expressed as attributes. XML supports mixed content (text alongside child elements), comments, processing instructions, namespaces, and schemas (XSD, DTD) — none of which exist in JSON. The key mapping challenge during conversion is XML attributes: fast-xml-parser represents them as @_attributeName keys in the JSON output. Arrays in JSON become repeated sibling elements in XML. A JSON null typically becomes an empty XML element.
| JSON construct | XML equivalent | Notes |
|---|---|---|
| Object {} | Parent + child elements | Keys become element tag names |
| Array [] | Repeated sibling elements | Same tag name repeated |
| String value | Text node | Inside the element tags |
| Number / boolean | Text node | Serialised as string in XML |
| null | Empty element or omitted | Convention varies |
| Key name | Tag name | Must be valid XML identifier (no spaces, starts with letter) |
XML attributes and namespace handling
XML attributes are metadata within an opening tag (e.g. <user id="42" active="true">). During XML-to-JSON conversion, fast-xml-parser maps these to @_id and @_active properties in the JSON object by default. During JSON-to-XML conversion, keys starting with @_ become attributes on the parent element. Namespaces (xmlns declarations) allow multiple XML vocabularies in one document and are preserved during conversion, though they add complexity when the resulting JSON is consumed by non-XML-aware systems. For REST API payloads, namespace-free XML is strongly preferred. When converting large XML documents with mixed content (XHTML, SVG), prefer a DOM-based approach over text-level transformation for accurate results.
Worked examples
JSON to XML
Inputs: {"user":{"id":1}}
Result: <user><id>1</id></user>
Attribute mapping
Inputs: <user id="42"/>
Result: JSON { "user": { "@_id": "42" } }
Array to repeated tags
Inputs: {"item":[1,2]}
Result: <item>1</item><item>2</item>
Glossary
- XML
- eXtensible Markup Language — a text-based format for structured data that uses opening and closing tags to define hierarchy.
- Attribute
- Metadata on an XML element expressed as name="value" inside the opening tag, distinct from child element content.
- Namespace
- A URI-based scoping mechanism in XML (xmlns:prefix="uri") that prevents element name collisions when combining vocabularies.
- XSD
- XML Schema Definition — a schema language for validating the structure and data types of an XML document.
- CDATA
- Character Data — an XML section (<!CDATA[ ... ]]>) where special characters like < and & are not interpreted as markup.
Related reading
Frequently Asked Questions
Why use JSON ↔ XML Converter?
- Convert a JSON API payload to well-formed XML for a SOAP service integration
- Transform an XML document back to JSON for consumption by a REST API or JavaScript client
- Handle XML attributes as @_key properties in JSON output using fast-xml-parser semantics
- Format the converted output with clean indentation for immediate readability
Common use cases
- Convert a REST API JSON response to XML to feed into a legacy enterprise SOAP pipeline
- Transform an XML config exported from an enterprise tool to JSON for version control
- Convert a JSON webhook payload to XML before forwarding to an XML-only third-party system
- Translate an RSS or Atom feed from XML to JSON for processing in a JavaScript aggregator
- Debug a JSON-to-XML conversion by checking how nested elements and attributes are mapped
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