JSON vs XML: Which Data Format Should You Use?

JSON and XML both structure data for exchange, but JSON is lighter and dominates modern APIs while XML remains common in documents and legacy systems.

Aspect JSON XML
Syntax Key/value, braces & brackets Tags & attributes
Verbosity Compact More verbose
Data types Native (string, number, bool, array, object) Everything is text
Comments No Yes
Schema / validation JSON Schema XSD, DTD
Best for APIs, web, config Documents, legacy, mixed content

The key difference

JSON is a compact, JavaScript-native format with built-in data types, which makes it ideal for web APIs and configuration. XML is more verbose but more expressive for documents — it supports attributes, comments, namespaces and mixed content (markup interleaved with text), which is why it persists in publishing, office formats and enterprise systems.

Which should you use?

For APIs, web apps and config files, use JSON — it is lighter, faster to parse in browsers and universally supported. Choose XML when you need rich document structure, attributes/namespaces, or must integrate with systems and standards (SOAP, RSS, office documents) that mandate it.

Work with JSON

JSON Formatter JSON Validator

Frequently asked questions

For web APIs and configuration, JSON is usually better — it is more compact, has native data types and parses easily in browsers. XML is better for rich documents and legacy or standards-driven systems.

JSON is lightweight, maps directly to JavaScript objects and native data types, and is faster and simpler to work with in web clients, which made it the default for modern APIs.

Standard JSON does not support comments, whereas XML does. This is one reason XML is sometimes preferred for human-edited configuration.