XML Formatter

XML Predates JSON by Two Decades and Still Runs Critical Systems

Despite JSON's dominance in modern APIs, XML is everywhere in enterprise software, system integrations, and legacy architectures. SOAP web services pass messages as XML envelopes. Android resource files — strings, layouts, manifests — are XML. Maven and Gradle build configurations are XML. RSS and Atom feeds are XML. Microsoft Office documents (.docx, .xlsx) are ZIP archives full of XML files. When you need to read, edit, or debug any of these, you need a tool that can parse and format the XML without installing anything.

This formatter uses the browser's native DOMParser — the same parser the browser uses internally — to achieve strict XML well-formedness validation. It catches every syntax error with a line and column number, then formats the valid XML with consistent indentation and an interactive element tree for exploration.

Well-Formed vs Valid — The Two Tiers of XML Correctness

XML has two distinct correctness requirements. Well-formedness is the basic syntax layer: every opening tag has a corresponding closing tag, elements are properly nested (you can't close an outer element before closing an inner one), every attribute value is quoted, special characters (< &) are escaped as entities, and there is exactly one root element. Any XML document that fails well-formedness is not valid XML — parsers must reject it.

Validity is the schema layer: even a well-formed document might not conform to the expected element structure. A SOAP envelope must have a specific Envelope/Body structure. An Android manifest must have specific required attributes. Validity requires a DTD or XML Schema document against which to check. This formatter validates well-formedness — the prerequisite for any further processing.

Reading Enterprise XML Formats in Practice

• SOAP responses from legacy web services: SOAP uses XML envelopes with defined Header and Body elements. Format the raw response to read the fault codes and payload data without manually parsing the namespace-heavy structure.
• Android development files: Format AndroidManifest.xml to verify permission declarations, layout XML to debug view hierarchy, and strings.xml to review all string resources before localisation.
• Maven POM files: Maven project configuration in pom.xml can be deeply nested with plugin configurations. Format to navigate dependency trees and plugin configurations before making changes.
• RSS and Atom feeds: Feed aggregators and feed validators expect well-formed XML. Format your feed output to verify the structure and validate it before publishing. Convert to JSON with the XML to JSON converter to inspect the data programmatically.
• SVG files: SVGs are XML. Format complex SVG files generated by design tools to understand their element structure, identify unnecessary groups, and debug rendering issues.
• Spring and Hibernate XML config: Older Java applications use XML for dependency injection and ORM mapping. Format these files to navigate bean definitions and relationship mappings.

Minification for API Payloads and Configuration

SOAP API requests sent over the network benefit from minification. XML interoperability layers in SOA architectures pass large numbers of messages — removing whitespace reduces message size and improves throughput. This formatter's minification removes all inter-element whitespace that is not significant text content, producing the most compact valid XML. The minified output passes any XML parser that accepted the formatted version. Use Format to expand it back for editing.

Privacy for Sensitive XML Data

This formatter uses the browser's native DOMParser and XMLSerializer APIs. No XML is transmitted to any server — not on format, not on minify, not on file upload. SOAP responses containing customer PII, XML configuration files with database passwords and API keys, and internal enterprise data feeds with proprietary business records can all be formatted safely here.

✓Verified by ToollyX Team · Last updated June 2026