Which conversions does it do?

JSON to YAML, YAML to JSON, and either of those to XML and back. That is six directed conversions from three formats.

What happens to very long numbers?

They are rounded, and the page says so. An id like 12345678901234567890 has more digits than a JavaScript number can hold, so it comes back as 12345678901234567000 — the converter now names any value it could not carry across rather than letting it change quietly. Quoting the value in the source carries it through untouched. Leading zeros depend on the format: coming from XML, an element holding 07030 stays 07030 rather than becoming 7030; in YAML a bare 07030 is read as the number 7030, which the page names so you can quote it; and JSON does not allow a leading zero on a number at all.

Why does my YAML come back looking different?

YAML has several ways to write the same data - quoted or bare strings, inline or block lists. The output picks one consistent style. If the data round-trips to the same JSON, nothing has been lost.

Can it convert deeply nested XML?

It handles ordinary nesting. XML carries things JSON has no equivalent for, such as attributes mixed with text content, so check anything unusual rather than assuming a clean round trip.

Is my config file uploaded?

No. The conversion happens in the page, which is worth knowing given how often a YAML config holds database passwords and API keys.

Does it validate as well as convert?

Effectively, yes - a document that will not parse cannot be converted, so an error tells you the input is malformed.

Stays on your computer How this works

Free JSON, YAML and XML converter

Convert between JSON, YAML and XML — entirely in your browser

JSON in

YAML out

XML needs exactly one root element, so converting into XML wraps the data unless it already has a single top-level key. Attributes are read and written with an @_ prefix.

About this JSON, YAML and XML converter

Converts in any direction between JSON, YAML and XML, with the structure preserved rather than flattened. A sample document is built in if you want to see the shape of the output before committing your own file.

Most often used to turn a JSON config into the YAML a tool expects, or to read an XML response as something more legible. It is free to use, with no account and no upload limit, and it runs entirely in your browser: nothing is uploaded, and while the page stays open, a feature you have already used keeps working offline.

What you can do

Convert JSON to YAML and YAML to JSON
Convert JSON or YAML to XML, and XML back to JSON or YAML
Paste a document or open a .json, .yaml, .yml or .xml file, with its format picked from the extension
Swap the direction with one click, feeding the result back in
Choose the indent and the name of the XML root element
XML attributes read and written, with an @_ prefix
Leading zeros in XML values kept, so 07030 stays 07030
Namespaced names such as dc:title, and names in any script, kept as they are; the <?xml ...?> declaration is left out of JSON and YAML
A warning naming any long number that would be rounded and any key renamed to be legal XML
An invalid document reports the parser’s error instead of converting
Copy the output or download the converted file

How to convert between formats

Paste the document in, or use Open file. There is a Sample to start from.
Set the format you are coming from and the one you want - the swap arrow reverses them.
The converted output appears alongside.
Copy it, or download the converted file.

Questions

Which conversions does it do?: JSON to YAML, YAML to JSON, and either of those to XML and back. That is six directed conversions from three formats.
What happens to very long numbers?: They are rounded, and the page says so. An id like 12345678901234567890 has more digits than a JavaScript number can hold, so it comes back as 12345678901234567000 — the converter now names any value it could not carry across rather than letting it change quietly. Quoting the value in the source carries it through untouched. Leading zeros depend on the format: coming from XML, an element holding 07030 stays 07030 rather than becoming 7030; in YAML a bare 07030 is read as the number 7030, which the page names so you can quote it; and JSON does not allow a leading zero on a number at all.
Why does my YAML come back looking different?: YAML has several ways to write the same data - quoted or bare strings, inline or block lists. The output picks one consistent style. If the data round-trips to the same JSON, nothing has been lost.
Can it convert deeply nested XML?: It handles ordinary nesting. XML carries things JSON has no equivalent for, such as attributes mixed with text content, so check anything unusual rather than assuming a clean round trip.
Is my config file uploaded?: No. The conversion happens in the page, which is worth knowing given how often a YAML config holds database passwords and API keys.
Does it validate as well as convert?: Effectively, yes - a document that will not parse cannot be converted, so an error tells you the input is malformed.