How do XML and JSON compare as API data formats?

Question

Accepted Answer

Both describe structured, nested data. XML uses start and end tags and is more verbose; JSON uses key/value pairs in braces and is more compact and easier to handle in code.

XML
JSON

Building block
Elements with start and end tags
Key/value pairs in { } objects

Lists
Repeated elements
[ ] arrays

Size and readability
Verbose: each name appears twice
Compact, easy to read and write

In code
Needs an XML parser
Maps directly to dicts and lists

Typical use in networking
NETCONF; RESTCONF also accepts it
REST APIs, RESTCONF

Neither is "better" in general. NETCONF is built on XML, and most modern REST APIs default to JSON. Many interfaces, RESTCONF among them, accept either one: the client says which it wants in the Accept and Content-Type headers.

	XML	JSON
Building block	Elements with start and end tags	Key/value pairs in `{ }` objects
Lists	Repeated elements	`[ ]` arrays
Size and readability	Verbose: each name appears twice	Compact, easy to read and write
In code	Needs an XML parser	Maps directly to dicts and lists
Typical use in networking	NETCONF; RESTCONF also accepts it	REST APIs, RESTCONF