JSON vs XML

Where JSON wins

A JSON object maps directly onto a dictionary or hash in essentially every modern language, so parsing produces something you can use immediately with no mapping layer.

• Far less verbose: no closing tags to repeat.
• Maps directly onto native language types.
• Native in browsers via JSON.parse, with no library needed.
• Simpler to read for straightforward record data.

Where XML wins

XML distinguishes attributes from elements, supports namespaces so vocabularies from different sources can coexist in one document, and has mature, widely implemented schema validation.

• Attributes, giving metadata a place separate from content.
• Namespaces, so two vocabularies can safely mix.
• XSD schema validation, far more mature than JSON Schema tooling.
• XPath and XSLT for querying and transforming documents.
• Mixed content: text and markup interleaved, as in real documents.

Security differences

XML parsers carry risks JSON parsers do not. External entity resolution can be abused to read local files or make outbound requests (XXE), and entity expansion can be used to exhaust memory — the "billion laughs" attack. Both are mitigated by disabling entity processing, which every parser should do by default on untrusted input.

Where each is still standard

XML remains the format for RSS and Atom feeds, sitemaps, SOAP services, SVG, the internals of Office documents and a great deal of enterprise and financial messaging. JSON is the default for REST and GraphQL APIs, configuration and logging. Neither is going away.

Example

The same record. XML separates the id attribute from the element content; JSON has only keys.

<user id="42" active="true">
  <name>Ada Lovelace</name>
  <email>ada@example.com</email>
</user>

{
  "id": 42,
  "active": true,
  "name": "Ada Lovelace",
  "email": "ada@example.com"
}

Frequently asked questions

• XML to JSON Converter Convert any XML document into readable JSON. In your browser
• JSON to XML Converter Convert JSON objects and arrays into well-formed XML. In your browser
• XML Formatter Indent XML so nested documents become readable. In your browser
• XML Validator Check that an XML document is well-formed. In your browser
• JSON Formatter Beautify, validate and sort JSON with precise error messages. In your browser

• JSON vs YAML Which to use for configuration and which for data interchange, and the YAML gotchas worth knowing.
• How to Convert XML to JSON Turn an XML document or feed into JSON, and handle the attributes and repeated elements that make it lossy.
• How to Format JSON Turn minified or broken JSON into something readable, and fix it when it will not parse.