{ } JSON vs < > XML
JSON vs XML: readability, verbosity, schema validation, namespace support, and when to choose each for APIs, config files, and data storage.
Use JSON for REST APIs, web applications, configuration files, and anywhere a lightweight, human-readable format is needed. Use XML for enterprise systems (SOAP, EDI, SAML), documents with complex structure and metadata, situations requiring strict schema validation (XSD), or legacy systems that mandate it.
JSON vs XML: Side-by-Side Comparison
| Property | JSON | XML |
|---|---|---|
| Verbosity | Compact, minimal syntax | Verbose, explicit open/close tags |
| Readability | Clean for simple structures | Dense for humans at scale |
| Comments | ❌ Not supported | ✅ Supported () |
| Attributes | ❌ Not a native concept | ✅ Elements can have attributes |
| Schema validation | JSON Schema (optional) | XSD (powerful, widely used) |
| Namespaces | ❌ Not supported | ✅ Full namespace support |
| Data types | string, number, bool, null, array, object | Everything is text (typed via XSD) |
| Common use cases | REST APIs, NoSQL, config, web | SOAP, SAML, Office docs, RSS/Atom |
When to use JSON
- REST API responses and requests
- NoSQL database storage (MongoDB, Firestore)
- Browser localStorage and cookies
- Modern application configuration (package.json, tsconfig.json)
- Single-page application data interchange
When to use XML
- SOAP web services and enterprise integrations
- SAML authentication (single sign-on)
- Microsoft Office file formats (DOCX, XLSX are ZIP + XML inside)
- RSS and Atom feeds
- Situations requiring powerful schema validation via XSD or Schematron
Frequently Asked Questions
Is JSON replacing XML?
JSON has replaced XML in most web and API contexts — REST APIs overwhelmingly use JSON. However, XML remains dominant in enterprise systems (SOAP, EDI, SAML), document formats (Office files, SVG, RSS), and situations requiring the sophisticated schema and namespace capabilities that XML provides.
Is JSON faster than XML?
JSON is generally faster to parse than XML because it is less verbose — there is less text to process. XML parsers must handle attributes, namespaces, and processing instructions that add overhead. For high-throughput APIs, JSON parsing is noticeably faster.
Can I convert JSON to XML?
You can format and validate JSON using the free JSON Formatter at allio.tools/tools/developer/json-formatter/, and format XML using the XML Formatter at allio.tools/tools/developer/xml-formatter/.
Does XML support arrays?
XML does not have a native array type — you represent sequences by repeating elements with the same tag name. JSON has a native array type ([]). This makes JSON more natural for representing lists and collections, and is one reason JSON is preferred for APIs that return collections of data.