XML vs. JSON: Why the Web Moved Away from Angle Brackets

XML's dominant era

In the late 1990s and through much of the 2000s, XML was the default format for web data exchange. SOAP-based web services, RSS feeds, and countless enterprise systems all standardized on XML, largely because of its rigor: strict, verifiable structure with schema validation (XSD), namespaces to avoid naming collisions, and a mature ecosystem of parsing tools across every major programming language.

Why JSON took over for web APIs

JSON, standardized in the early-to-mid 2000s, offered a much lighter alternative for the specific case that mattered most as web applications grew: sending structured data between a server and JavaScript running in a browser. JSON maps directly onto native JavaScript objects with no parsing step needed in that context, while XML required additional parsing work and produced noticeably more verbose output for the same data — extra bytes that matter at web scale. As JavaScript-heavy web applications became the norm, JSON's simplicity for exactly that use case gave it a decisive advantage.

What JSON deliberately left out

JSON's simplicity is also a limitation: it has no built-in schema validation standard as universally adopted as XSD, no native support for comments (see our JSON article on that exact topic), and no equivalent of XML namespaces for combining vocabularies from different sources without naming collisions. These aren't oversights so much as trade-offs — JSON chose simplicity over XML's more elaborate feature set.

Where XML never actually left

XML remains the standard in several domains where its stricter validation and mature tooling still matter: many enterprise and financial systems (SOAP-based services persist widely in banking and government), document formats (the .docx, .xlsx and .pptx Office formats are technically ZIP archives full of XML files), and configuration formats for some Java and Android ecosystems, RSS/Atom feeds, and SVG images, which are themselves an XML-based format.

Working with XML today

Whether you're maintaining a legacy SOAP integration or just need to read an RSS feed, well-formatted XML is far easier to work with than a single unindented line. Our XML Formatter validates that your XML is well-formed and reformats it with clean, nested indentation using the browser's native XML parser.