JSON vs XML: Which Format Should You Use?
What is the difference between JSON and XML?
JSON is a lightweight data format with native types like numbers, booleans, and arrays, born from JavaScript. XML is a markup language with attributes, namespaces, and a document model, built for documents as much as data. JSON wins for APIs and configuration. XML still leads where documents, namespaces, or strict schemas matter.
The short version
Reach for JSON when you are moving data between systems, especially web APIs and configuration. Reach for XML when you are moving documents, or when namespaces, mixed content, or XSD validation are part of the job. Both are widely supported and converting between them is routine.
How they look
JSON uses braces, brackets, and colons, and a person, a list of names, and a flag read naturally. XML wraps every value in an opening and closing tag, with attributes available for metadata. The same data takes more characters in XML, and that verbosity is the price of being a markup language.
- JSON: {"name": "Ada", "roles": ["admin"]}
- XML: <person name="Ada"><roles><role>admin</role></roles></person>
Data types
JSON has real types: strings, numbers, booleans, null, arrays, and objects. XML has no types of its own. Everything inside an element is text until a schema or a parser decides otherwise, and XML attributes are always strings too. That makes JSON faster to consume in typed environments and XML more literal about documents.
Schema and validation
JSON Schema validates structure and types and is widely supported across languages. XML has DTD and XSD, which are older and more verbose but very mature. If your industry already lives on XSD contracts, XML is the pragmatic choice. If you control the contract, JSON Schema is usually simpler to maintain.
Where each format wins
JSON dominates web APIs, config files, and the JavaScript ecosystem. XML remains entrenched in documents, SOAP web services, publishing, and any stack with a heavy XSD dependency. Neither is going anywhere, and most real systems pass data between both at some boundary.
Converting between them
When a system hands you XML but your code wants JSON, convert it with a tool that maps attributes and repeated tags predictably. The reverse, JSON to XML, needs a decision about how arrays and types become elements and text. Both converters on this site run entirely in your browser.
FAQ
Is JSON always better than XML?
No. JSON is more compact and typed, but XML handles documents, namespaces, and mixed content better. The right choice depends on the consumer, not fashion.
Can XML represent a number or a boolean?
Not natively. Everything in an XML element is text until a schema or parser assigns a type. JSON stores these types directly.
Why does older software still use XML?
XML predates JSON and powers a lot of enterprise infrastructure: SOAP services, XSD contracts, and document pipelines. Migration costs keep it in place even where JSON would be lighter.
How do I convert between JSON and XML?
Use a converter. JSON to XML maps objects to elements and arrays to repeated tags. XML to JSON maps attributes to @-prefixed keys and repeated tags to arrays. Both directions run locally on this site.