XML Formatter

What is an XML Formatter and Why Use One?

<!-- Minified XML input -->
<?xml version="1.0" encoding="UTF-8"?><catalog><product id="p01"><name>Wireless Headphones</name><price currency="USD">79.99</price></product></catalog>

<!-- After formatting with 2-space indent -->
<?xml version="1.0" encoding="UTF-8"?>
<catalog>
  <product id="p01">
    <name>Wireless Headphones</name>
    <price currency="USD">79.99</price>
  </product>
</catalog>

Key Features

Examples

<?xml version="1.0" encoding="UTF-8"?><catalog><product id="p01" category="electronics"><name>Wireless Headphones</name><price currency="USD">79.99</price><stock>142</stock><tags><tag>audio</tag><tag>bluetooth</tag></tags></product><product id="p02" category="books"><name>Learning XML</name><price currency="USD">29.99</price><stock>55</stock></product></catalog>

<rss version="2.0"><channel><title>Go Tools Blog</title><link>https://go-tools.org/blog</link><description>Developer tools, tips and tutorials</description><item><title>Understanding XML Namespaces</title><link>https://go-tools.org/blog/xml-namespaces-guide</link><pubDate>Thu, 29 May 2026 00:00:00 GMT</pubDate><description>A deep dive into XML namespace declarations, prefixes, and scope rules with practical examples.</description></item><item><title>XML vs JSON: When to Use Each</title><link>https://go-tools.org/blog/xml-vs-json</link><pubDate>Mon, 25 May 2026 00:00:00 GMT</pubDate></item></channel></rss>

<soap:Envelope xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"><soap:Header><wsse:Security xmlns:wsse="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-secext-1.0.xsd"><wsse:UsernameToken><wsse:Username>api-client</wsse:Username><wsse:Password Type="http://docs.oasis-open.org/wss/2004/01/oasis-200401-wss-wssecurity-ext-1.0.xsd#PasswordText">s3cr3t</wsse:Password></wsse:UsernameToken></wsse:Security></soap:Header><soap:Body><GetOrderRequest xmlns="http://example.com/orders"><OrderId>ORD-20260529-001</OrderId><IncludeLineItems>true</IncludeLineItems></GetOrderRequest></soap:Body></soap:Envelope>

How to Use

1. 1

   Paste Your XML

   Enter or paste your XML into the input field above. You can also click 'Load example' to try a sample (a minified product catalog XML that formats nicely).

2. 2

   Choose an Action

   Click Format to beautify with indentation, Minify to strip whitespace, or Validate to check well-formedness. Select 2 or 4 spaces for the indent size before formatting.

3. 3

   Copy the Output

   The processed XML appears in the output panel. Click Copy to grab it to your clipboard. If Validate found errors, the error banner shows the exact line and column number.

Common XML Errors

<products>
  <Item>
    <name>Widget</name>
  </item>
</products>

<products>
  <item>
    <name>Widget</name>
  </item>
</products>

<query>price > 10 & stock > 0</query>

<query>price &gt; 10 &amp; stock &gt; 0</query>

<product id=p01 label="It's a "widget"">

<product id="p01" label="It's a &quot;widget&quot;">

<user><name>Alice</name></user>
<user><name>Bob</name></user>

<users>
  <user><name>Alice</name></user>
  <user><name>Bob</name></user>
</users>

<?xml version="1.0" encoding="UTF-8"?>
<!-- File is actually saved as UTF-16 -->

<?xml version="1.0" encoding="UTF-16"?>
<!-- File saved as UTF-16, declaration matches -->

<script><![CDATA[
  if (a < b && b > c) { return true; }
<!-- ]]> is missing -->

<script><![CDATA[
  if (a < b && b > c) { return true; }
]]></script>

Common Use Cases

Debugging SOAP / Web Service Payloads

SOAP responses from enterprise APIs and legacy web services arrive as single-line XML strings. Paste the raw payload into the formatter to instantly see the envelope structure, headers, and body — making it easy to find the field you need or spot a namespace mismatch. See also: XML to JSON Converter if you need to process the payload further in JavaScript.

Validating Config Files and Deployment Descriptors

Maven POM files, Spring XML application contexts, Tomcat server.xml, Android Manifest files, and many other Java/enterprise configuration files are XML. Run them through Validate before committing to catch mismatched tags or encoding issues that would otherwise only surface at build or deploy time.

Formatting RSS and Atom Feed Output

RSS 2.0 and Atom 1.0 feeds are XML. When developing a feed generator or debugging feed reader compatibility issues, format the raw feed XML to inspect the channel metadata, item structure, and required namespace declarations side by side.

Reading and Editing SVG Files

SVG files exported from Figma, Illustrator, or Sketch are valid XML but are often minified or contain excessive indentation from the exporter. Format the SVG to get a clean, navigable element tree before making manual edits to paths, groups, or styling attributes.

Preparing XML for Storage or Transmission

When storing XML in a database column, sending it as a JSON string field in an API request, or inserting it into a message queue, use Minify first to strip unnecessary whitespace. This reduces payload size and avoids issues with JSON parsers that may choke on unescaped control characters in large indented XML strings.

Converting XML to JSON

If you need to convert your formatted XML to JSON for use in a JavaScript application or REST API, use our XML to JSON Converter. For the reverse — building XML from a JSON structure — use the JSON to XML Converter.

Technical Details

Browser DOMParser for XML Parsing

XML parsing uses the browser's native DOMParser with the 'text/xml' MIME type. This is the same engine that powers SVG and XHTML rendering in the browser — it is fully XML 1.0 compliant and reports well-formedness errors with line and column information. When the document is not well-formed, DOMParser returns a parsererror document containing the error message and position, which this tool extracts and displays.

DOM Tree Serialization for Formatting

Formatting works by parsing the XML into a DOM tree and then walking the tree recursively to produce indented output. This approach preserves the semantic structure of the document: element nesting, text content, attributes, CDATA sections, processing instructions, and comments are all serialized back exactly as parsed. Only inter-element whitespace-only text nodes are discarded — text nodes that contain non-whitespace characters are always preserved.

Minification via Whitespace-Only Text Node Removal

Minification traverses the same DOM tree and removes text nodes whose content is entirely whitespace (spaces, tabs, newlines). Text nodes with mixed or non-whitespace content — the actual data between tags — are never removed. Attributes and their values are serialized without added whitespace. The result is the most compact well-formed XML representation of the original document.

100% Browser-Based — No Upload, No Server

All processing runs in your browser's JavaScript runtime. No data is transmitted to any server at any point. This is especially important for XML payloads that frequently contain sensitive content: SOAP WS-Security tokens, HL7 patient data, internal service configuration, and financial message formats (FIX, SWIFT ISO 20022). The tool is safe to use with any XML that you would not want to paste into a public service.

Best Practices

Validate Before Formatting, Format Before Committing

Validate your XML first to confirm it is well-formed before reformatting — the formatter will silently produce incorrect output if the input is not valid XML. Once validated, format and review the indented output before committing config files, feed templates, or WSDL definitions to version control.

Use 2-Space Indent for Web Formats, 4-Space for Enterprise XML

Two-space indentation is the convention for RSS/Atom feeds, SVG, XHTML, Android XML, and most web-facing XML. Four-space indentation is common in Java enterprise environments (Maven POM, Spring context files, JBoss deployment descriptors). Match the convention of your existing files and toolchain.

Minify XML Before Embedding in JSON

If you need to embed an XML string as a JSON field value, always minify it first. Indented XML contains newlines and multiple spaces that must be JSON-escaped (\n, multiple \u0020), dramatically inflating payload size. Minified XML is also far less likely to trigger line-length limits in intermediary proxies or logging systems.

Escape Special Characters in Text Content, Use CDATA Sparingly

For short text values containing & or <, use entity references (&, <) — they are more portable than CDATA sections and work in attribute values too. Reserve CDATA sections () for embedding large blocks of code, SQL queries, or HTML fragments where escaping every special character would make the content unreadable.

Declare Namespaces as Early as Possible

Declare XML namespaces (xmlns:prefix="URI") on the root element or the highest-level element that uses the prefix. Declaring namespaces deep in a document tree makes the XML harder to read and can cause issues with stream-based XML parsers (SAX, StAX) that process namespaces incrementally. The SOAP Envelope example above demonstrates the recommended pattern: all namespace declarations on the root Envelope element.

Frequently Asked Questions