XML Formatter / Validator
XML (eXtensible Markup Language) is a standard format for structured data exchange, widely used in web services (SOAP), configuration files, RSS feeds, and enterprise integrations. Proper formatting makes XML documents easier to read and debug.
This tool formats, minifies, and validates XML documents. It detects syntax errors like unclosed tags or invalid nesting, and lets you choose your preferred indentation size for formatted output.
How it works
XML uses a tree structure with opening and closing tags. Every element must be properly nested and closed. Attributes are placed inside opening tags as key="value" pairs.
Use cases
- Formatting SOAP API request and response payloads
- Validating XML configuration files before deployment
- Minifying XML for reduced payload size in data transfers
- Debugging RSS/Atom feed markup issues
Frequently asked questions
How do I format an XML file online?
Paste your XML into the tool and it re-indents the document into a readable tree structure, with each nested element on its own line. You can choose your preferred indentation size for the output. Formatting only changes whitespace — the data itself stays identical.
What makes an XML document well-formed?
A well-formed XML document has exactly one root element, every tag properly closed, elements correctly nested without overlapping, and attribute values enclosed in quotes as key="value" pairs. Tag names are also case-sensitive, so <Item> and <item> are different elements. This validator flags violations such as unclosed tags and invalid nesting.
What does minifying XML do?
Minification removes the whitespace and line breaks between tags, collapsing the document into a compact single-line form. This reduces payload size for data transfers and API calls without changing the document's structure or content. Formatting is the reverse operation — it re-expands minified XML for readability.
How can I find syntax errors in my XML?
Paste the document into this validator and it detects common problems such as unclosed tags, mismatched opening and closing tags, and invalid nesting. Fix the reported issue and re-validate until the document parses cleanly. This is especially useful for debugging SOAP payloads and RSS/Atom feed markup.
Is XML still used today?
Yes. XML remains the standard for SOAP web services, RSS and Atom feeds, many enterprise integrations, and countless configuration file formats (such as Maven's pom.xml and Android layouts). While JSON dominates newer REST APIs, large amounts of business-critical infrastructure still exchange data as XML.