JSON to YAML

Paste JSON data and get YAML back instantly — no upload, no account, no waiting. The conversion runs in your browser with the js-yaml library, so your data never leaves your device. Copy the result, or download it as a .yaml file ready for a config file, a CI pipeline, or a Docker Compose setup.

YAML is the configuration-file cousin of JSON: the same data, but with indentation instead of braces and no quotes around most strings. That makes it easier to read — and easier to break with one wrong space. If the data belongs in a spreadsheet instead, the JSON to CSV converter is the better stop, and JSON to XML fits systems that still speak XML.

How does JSON to YAML work?

JSON to YAML rewrites the same data with indentation instead of braces: each key sits on its own line, nested objects indent two spaces deeper, and arrays become dash-prefixed lines. The data does not change at all — {"name": "Alex"} and name: Alex describe exactly the same value.

Quoting is where YAML gets subtle, and js-yaml handles it for you: a string that looks like a number, a date, or a yes/no word gets quotes, so zip "78701" stays a string instead of becoming the number 78701, and answer "yes" stays the word yes instead of becoming the boolean true. A real null becomes the word null, not an empty value, and true and false stay lowercase.

What happens to tricky values

Indentation is the whole format: two spaces per level, every level, no tabs. A line indented by three spaces instead of two belongs to a different parent, and most parsers will either fail or silently read a different structure. If your YAML loads but the values land in the wrong place, count the spaces first — it is the cause nine times out of ten.

Worked example: an editor profile becomes YAML

Press Sample and the tool loads a short profile: a name, a role, two tags, and an active flag. Watch how each type changes shape: strings lose their quotes, the tags array becomes two dash lines indented under tags, and the boolean true stays lowercase. The key order is unchanged.

Example input:

{"name":"Alex","role":"editor","tags":["news","sport"],"active":true}

Becomes:

name: Alex\nrole: editor\ntags:\n - news\n - sport\nactive: true

Try it yourself: add a third tag to the JSON array and watch a third dash line appear in the YAML. Then change editor to admin — notice the quotes vanish again, because admin is not a word YAML would misread. That is the rule: js-yaml quotes only when the meaning would change without them. If the input is messy, tidy it first with the JSON Formatter.

When should I choose YAML over JSON?

Choose YAML when a human has to read or edit the file regularly — config files, CI pipelines, and Docker Compose are the classic cases — because indentation is easier on the eyes than braces. Choose JSON when a program reads the file and nobody edits it by hand, since JSON is stricter and parsers never argue about spaces.

YAML's readability is also its risk: a file that looks fine can hide a wrong indent, while JSON either parses or it does not. Keep JSON as the stored format when you can, and generate YAML from it with this tool whenever a human needs to touch the file.