XML Formatter
Format XML with readable indentation while preserving elements, attributes, text, comments, and escaped values.
Make XML structure easier to read
Compact XML is efficient to transmit but difficult to inspect. An element, attribute, closing tag, or escaped character can be hard to locate when everything is on one line. This formatter presents a readable layout so you can review the document structure before using it in a build, request, or configuration workflow.
Formatting changes presentation rather than the intended XML data. It should preserve element names, attribute values, text nodes, comments, and entity references while adding consistent indentation and line breaks. A readable result is easier to review, but it is not a schema validation result.
Use a small representative sample when learning the tool. Keep the source document, the formatted copy, and any downstream validation result separate so you can tell whether a later problem is caused by XML syntax, a schema, encoding, or application rules.
Formatting is not validation
XML is a nested markup format made of elements, attributes, text, comments, declarations, and character references. Elements need matching start and end tags, attributes belong to a start tag, and reserved characters such as ampersand must be escaped when they are data.
A formatter parses enough structure to arrange nodes and whitespace. It does not prove that the document matches an XSD, DTD, application contract, namespace policy, or business rule. Keep those checks in the workflow that owns them.
Whitespace can be data in some XML contexts, including mixed content and text nodes. Before changing a document used by a whitespace-sensitive consumer, compare the formatted output with that consumer's requirements and preserve the original source.
How to format XML
- Paste one XML document or a complete fragment into the source field. Remove unrelated prose or a programming-language wrapper from the test copy.
- Run the formatter and inspect the resulting nesting, attributes, comments, and text values. A formatting failure should be treated as a reason to inspect the source, not as proof of a particular parser message.
- Compare the formatted document with the original. Confirm that element names, attribute values, entity references, namespace declarations, and character data are unchanged.
- After formatting, run the XML parser, schema validator, or application test required by your project. Formatting alone does not establish validity or compatibility.
- For production data, remove secrets and personal information from the sample. Keep the original file available for a controlled diff and rollback.
Formatting method
- Read XML structure
The tool reads the supplied markup as nested XML content and identifies element boundaries, attributes, text, comments, and declarations that can be laid out.
- Apply indentation
The formatter adds line breaks and indentation to make parent and child relationships visible. The chosen whitespace is presentation output, not a new schema rule.
- Preserve technical values
Values such as attribute text, entity references, namespace prefixes, and comment content must remain tied to the source sample. Review a diff when the exact bytes matter.
The public page documents formatting input. Exact parser recovery behavior, whitespace policy, and error wording should be confirmed in a live engine before being described as fixed behavior.
Read the formatted result
A successful result is a readable arrangement of the supplied XML. Confirm that the tree, values, attributes, comments, and declarations match the source.
A failure means the input could not be handled by the documented formatter path. Do not infer an exact parser rule or error location without matching runtime evidence.
If the formatted document later fails an XSD or application check, investigate that separate contract. Formatting does not add required elements, namespaces, or types.
Common mistakes
Treating indentation as schema validation can hide missing required elements or invalid attributes.
Replacing escaped entities with visible characters may change XML data or make the document invalid.
Sorting attributes or children for visual preference can change a consumer's expected order or mixed content.
Copying only a fragment without its required namespace declaration can make a test unlike the production document.
Limits and special cases
The documented capability is XML formatting. It does not establish XSD or DTD validation, transformation, canonicalization, security scanning, or application compatibility.
Whitespace-sensitive mixed content, processing instructions, namespaces, large documents, and parser-specific recovery behavior should be tested with the target consumer.
Do not paste confidential production documents unless your handling policy permits it. A formatted copy may still contain the same sensitive values.
Examples
Format a simple element
Can a compact element be made readable?
Submit the compact XML.
The child elements are placed on separate indented lines under note.
Keep attributes visible
How should an element with an attribute be reviewed?
Submit the element and inspect the opening tag.
The id attribute stays on user while the child name is indented.
Preserve escaped text
Can text containing an entity remain intact?
Format the document and compare the text node.
The entity reference remains part of the text representation.
Format repeated children
Can repeated elements be separated clearly?
Submit the parent with two item children.
Each repeated child appears on its own line, making order easier to review.
Keep a comment
What should happen to an XML comment?
Format the configuration sample.
The comment remains in the document between the parent and mode element.
Keep a declaration
How should a declaration be handled?
Submit the declaration and root element together.
The declaration stays at the beginning and the root content is indented below it.
Frequently asked questions
Does formatting validate an XML schema?
No. Formatting lays out the XML structure. Use the XSD, DTD, or application validator required by the project for schema checks.
Will formatting change my element values?
It should preserve the supplied values and structure while adding presentation whitespace. Compare the output with the original when exact text matters.
Are comments preserved?
The examples treat comments as XML content to keep in the formatted view. Confirm behavior for your exact input before relying on it in a pipeline.
Can I format an XML fragment?
Use a complete document or a documented fragment shape. A fragment may depend on a namespace or surrounding root that is missing from the pasted sample.
Does indentation make XML smaller?
No. Indentation usually adds whitespace for readability. Use a separate minifier or transport process when compact output is required.
What about escaped ampersands?
Keep entity references such as & as XML data. Do not replace them with a raw ampersand unless the resulting context is valid XML.
Can formatting repair malformed XML?
Do not assume automatic repair. Fix the source deliberately and verify it with the parser and schema checks used by the application.
What should I do after formatting?
Review a diff, run the required parser or schema checks, and test the formatted copy with the real consumer if whitespace or namespaces matter.