YAML to XML Converter

How to use the yaml to xml converter

1. Paste or type your YAML document into the input area.
2. Optionally change the root element name if you need a specific wrapper tag for your XML schema.
3. The XML output updates automatically as you type.
4. Copy the resulting XML for use in your application or pipeline.

How the conversion works

YAML and XML represent hierarchical data differently. A YAML mapping becomes a series of child elements inside the parent key's element. For example, the YAML name: Alice nested under person: produces <person><name>Alice</name></person>.

Sequences are converted using an <item> wrapper element because XML does not have a native list construct. Flow collections like [a, b] and {x: 1} are parsed identically to their block equivalents before conversion.

All scalar values are escaped according to XML rules. Characters such as &, <, >, and " are replaced with their entity references to ensure the output is well-formed. If you need to inspect the result further, you can use an XML viewer or format the XML for readability.

Supported YAML subset

This converter implements a practical subset of YAML 1.2 rather than the full specification. The goal is to handle the structures most commonly found in configuration files and data exports while keeping the parser small and dependency-free.

If your YAML uses anchors or tags, resolve them first or convert through JSON as an intermediate step. This avoids silently producing incorrect XML.

Mapping YAML keys to XML elements

XML element names have stricter rules than YAML keys. A valid XML name must start with a letter or underscore and may contain letters, digits, hyphens, underscores, and periods. When a YAML key contains spaces or other invalid characters, this converter replaces them with underscores.

For example, the YAML key first name becomes the XML element <first_name>. Numeric keys like 42 are prefixed with an underscore to produce <_42>, since XML names cannot begin with a digit. Duplicate keys within the same mapping will each produce a separate element, which is permitted in XML but may cause issues with strict parsers.

If you need to reverse the process, the XML to YAML tool converts elements back into YAML mappings.

Common use cases

Converting YAML to XML is frequently needed when integrating modern configuration formats with legacy systems that expect XML. Build tools, enterprise service buses, and SOAP-based APIs often require XML payloads even when the source data lives in YAML files.

Another common scenario is generating XML sitemaps or RSS feeds from structured data maintained in YAML. Developers keep content metadata in YAML for readability, then transform it at build time. Because this converter runs entirely in the browser, it is suitable for quick one-off conversions without installing command-line utilities.

When working with mixed data pipelines, you might also need to extract tabular data from XML or compress XML output for transmission.

Edge cases and pitfalls

A few edge cases deserve attention when converting YAML to XML. First, YAML allows multiple documents separated by ---. This converter handles a single document and returns an error for a multi-document stream, so split the stream first. A single leading --- is fine.

Second, null values in YAML (written as null, ~, or left empty) become self-closing XML elements like <key/>. Boolean values true and false are serialized as lowercase text content, matching the YAML 1.2 core schema, and numbers are copied exactly as written (1.50 stays 1.50). If a value contains a control character that XML 1.0 cannot hold, such as a null character written as "\0", the tool reports an error instead of producing broken XML.

Third, deeply nested structures produce correspondingly deep XML trees. While there is no hard limit enforced by this tool, extremely deep nesting may cause performance issues in downstream XML parsers. Keep your structures reasonably flat when possible.

Worked examples