YAML to JSON
Turn an indented configuration file into JSON, with a proper line and column when the indentation is wrong. Values YAML resolves to dates or infinities are converted in a way you can see rather than silently becoming null, and multi-document files are handled as a single array.
Reads every document separated by a document break and writes one array.
How yaml to json works
- Paste the YAMLOne document, or several separated by a document break if you turn the option on.
- Read the conversion notesDates, infinite values and very large integers are reported rather than hidden.
- Take the JSONDownload it or copy it, with the usual two-space indentation.
What you get
Convert a YAML document to JSON, and see where the types shift. Everything happens inside this page: the file is read by your browser, transformed in memory and handed straight back to you as a download. There is no upload queue, no waiting for a server, and nothing left behind when you close the tab.
Supported formats
This tool works on text you paste or type, so there is no file format to worry about. Nothing you type is sent anywhere.
Limitations, stated up front
- YAML tags, custom types and merge keys beyond plain anchors are resolved or ignored rather than preserved; JSON has nowhere to put them.
- Very large integers become strings, because JavaScript numbers stop being exact above 2^53.
Frequently asked questions
Why is my date now a string?
Because YAML decides that an unquoted 2026-01-01 is a timestamp, while JSON has only strings, numbers, booleans, null, arrays and objects. Furtu writes the date as an ISO 8601 string and tells you how many values were affected. Quote it in the source if you want it to stay text.
What happens to infinite values and not-a-number?
JSON cannot represent them, so they are written as null and counted in the notes. Silently dropping them would be worse: null looks like a value somebody chose.
Why does it fail on a file my editor says is fine?
Because YAML forbids tabs for indentation, and an editor will happily show you a file that mixes a tab and spaces. The error Furtu reports includes the line and column and the nearby text, which is usually the whole diagnosis.
Are anchors and aliases resolved?
Yes. An alias is expanded to the value it refers to, so the JSON is self-contained. The cost is size: a shared block repeated twenty times appears twenty times.
Is my YAML uploaded?
No. Parsing happens in your browser, which is the point when the file is a Kubernetes manifest or a CI config containing registry credentials.