TOON to YAML converter
Paste TOON on the left, read YAML on the right, and switch direction or target format with the pickers above. The conversion runs in your browser: nothing you paste is uploaded, which matters when the document is a config file or a client export.
Text is processed by your own browser and never leaves your device: this page has no server to send it to.
How it works
The document is parsed into a plain data structure and re-serialised into YAML. JSON is the pivot in the middle, which is why the four formats on this hub all reach each other: adding a format gives you every direction with it, not just one pair.
TOON writes an array's repeated keys once as a header row, which is why it costs fewer tokens than JSON when the payload goes into a prompt.
YAML carries the same shapes with indentation instead of braces, and quotes only what would otherwise change type, so version: 1.0 stays a number and version: '1.0' stays a string.
Frequently asked questions
Is my data uploaded anywhere?
No. The parser and the serialiser both run in this page, and the converter chunk downloads on your first keystroke rather than with the page. You can check it yourself: open the network tab, paste something, and watch that no request carries your text.
Does the conversion preserve everything?
Between TOON and YAML, yes for the shapes both formats can express: nesting, arrays, strings, numbers, booleans and null all survive, and key order is preserved. What no format here can carry is anything JSON itself cannot, such as a date object or a comment.
Which format should I actually use?
Our rough rule: JSON for APIs and anything a program reads, YAML for files a person edits by hand like CI config, CSV for anything headed to a spreadsheet, and TOON only when you are pasting a lot of uniform records into a prompt and paying per token. Converting is cheap; picking the wrong home format for a file you edit weekly is not.