XML vs JSON: when to use each
How XML and JSON differ in syntax, attributes, schemas and tooling, and which format fits your use case.
Syntax and verbosity
XML wraps every value in a named open and close tag, which is verbose but self-describing. JSON uses braces, brackets and key-value pairs, which is more compact and maps directly to objects and arrays in most languages.
Attributes and metadata
XML can attach attributes to an element, such as an id or language on a tag, and supports namespaces. JSON has no attribute concept, so metadata becomes ordinary keys, which keeps the model simpler but flatter.
Schemas and validation
XML has mature schema languages like XSD and DTD plus XPath and XSLT for querying and transforming documents. JSON Schema covers validation well and is widely supported, while query tooling is lighter weight.
When to choose which
Reach for XML when you need rich document markup, mixed content or strict schemas, for example in publishing, SOAP services and config formats. Reach for JSON for most web APIs and config where compactness and native parsing matter.