Convert JSON to YAML

How to use it#

1. Drop a .json file on the box at the top, or paste your JSON into the text box under it. A dropped file opens in the text box, where you can edit it.
2. Pick 2 or 4 spaces of indentation.
3. Tick sort keys if you want them alphabetical rather than in the order they arrived.
4. Copy the result, or download it as a .yaml file named after the one you dropped.

Why anyone converts this way#

JSON is what a machine sends and YAML is what a person edits. The moment a payload becomes something a human has to maintain, a Kubernetes manifest, a CI pipeline, a docker compose file, the brackets and quotes start getting in the way and the indentation starts helping.

YAML also lets you add comments, which is usually the reason for the conversion. A config nobody can annotate is a config nobody can hand over.

What you get back#

Keys keep the order they arrived in by default, because in a hand-written config that order usually carries meaning: the important settings sit at the top. Sort keys puts them in alphabetical order instead, which is the better choice when two files are about to be compared, since a diff of two sorted files shows only what actually differs.

Long strings are written on one line rather than folded. YAML is allowed to wrap a long value across several lines, and it means the same thing, but a URL broken over three lines is alarming to read and easy to break by editing carelessly.

A string that would otherwise be read as something else comes back quoted. The value "3" is written as '3' so it stays a string, which is the difference between a version number and a number.

YAML is stricter than it looks#

The indentation is the structure, so it has to be spaces. Tabs are not permitted for indentation anywhere in YAML, and an editor set to insert tabs will produce a file no parser accepts. Most editors can be told to use spaces for .yaml and .yml files specifically.

The other thing to watch is that YAML is a superset of JSON, which means your original JSON was already valid YAML. Converting it is about readability, not about compatibility, and anything that accepts YAML would have taken the JSON as it was.

Numbers, repeated keys, and dates#

Numbers are copied as written. A 20 digit ID, too long for a JavaScript number, keeps every digit, and 1.50 stays 1.50 rather than becoming 1.5. A key that appears twice in one object is written once, with its last value, because YAML does not allow a repeated key and the last value is what JSON readers keep.

Anything not expressible in JSON to begin with, such as a date object or a function, is not in your input either: by the time it is JSON it is a string, a number, or nothing. The conversion cannot recover a type that was already flattened.