JSON to YAML Converter

What this JSON to YAML converter does

The converter parses your input with the browser’s JSON.parse and writes it out as block-style YAML using the open-source js-yaml library (version 4). Objects become indented mappings, arrays become - list items, numbers, booleans and null keep their types, and any string that YAML could misread is quoted so that the YAML means exactly what the JSON meant.

Every JSON document is already valid YAML 1.2, so the point of converting is readability: the block style drops braces, brackets and most quotes, and once the data is in YAML you can add # comments, which JSON does not allow. That is why Kubernetes manifests, Docker Compose files, GitHub Actions workflows and OpenAPI documents are usually written in YAML even when tools generate or consume JSON.

How to use the converter

1. Paste JSON into the JSON Input pane, or load it with File or URL (a URL must allow cross-origin requests).
2. Choose an Indent of 2 spaces or 4 spaces.
3. Click Convert. Invalid JSON produces an error starting with Invalid JSON:, followed by your browser’s own message, which differs between browsers.
4. Copy the YAML, Download it as converted.yaml, or Clear both panes.

The output pane opens on a tree of your JSON input, which is handy for checking structure before converting. Tree Viewer switches back to it after a conversion, and clicking a node copies its path.

Options explained

• 2 spaces — the most common style in YAML configuration files. List items are indented under their key (ports: then - port: 80).
• 4 spaces — wider indentation. With this setting js-yaml places the - of a list item that holds an object or another list on its own line, with the content indented below it. That is valid YAML, but it looks different from hand-written files; choose 2 spaces if you want the familiar - name: Install layout.

Long strings are never folded onto several lines, and the output does not start with a --- document marker.

What changes between JSON and YAML

Keys are quoted by the same rules, so a key named n or "0" comes out as 'n' or '0'. Accented letters and emoji are written as they are. To see why these quoting rules matter, read YAML pitfalls.

Example: a Kubernetes Service

{"apiVersion": "v1", "kind": "Service",
 "metadata": {"name": "web", "labels": {"app": "web"}},
 "spec": {"ports": [{"port": 80, "targetPort": 8080}], "selector": {"app": "web"}}}

converts with 2-space indentation to:

apiVersion: v1
kind: Service
metadata:
  name: web
  labels:
    app: web
spec:
  ports:
    - port: 80
      targetPort: 8080
  selector:
    app: web

Common problems and fixes

Frequently asked questions

Guides

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