JSON to YAML Converter

This converter turns JSON into YAML for Kubernetes manifests, Docker Compose files, GitHub Actions workflows and other configuration, and turns YAML back into JSON for APIs and code. It runs in your browser with a full YAML 1.2 parser, so anchors, merge keys, block text and multi-document files are handled properly, and syntax errors are reported with the line and column.

The Same Data in JSON and YAML

{
  "name": "web",
  "replicas": 3,
  "ports": [80, 443],
  "env": {
    "DEBUG": "no",
    "TZ": "Asia/Karachi"
  }
}

name: web
replicas: 3
ports:
  - 80
  - 443
env:
  DEBUG: "no"
  TZ: Asia/Karachi

YAML drops the braces, brackets and most quotes and shows nesting with indentation instead. Lists use a dash per item. "no" stays quoted because a YAML 1.1 reader would otherwise read it as false.

Values YAML Readers Disagree On

Unquoted, these values mean different things depending on the YAML version of the program reading them:

When converting JSON to YAML, strings like these are always written in quotes, so the result reads the same everywhere. When converting YAML to JSON, choose the version your tool uses to see what it will actually get.

YAML Rules That Cause Most Errors

• Indent with spaces only. Tabs are not allowed for indentation, and items at the same level must line up exactly.
• Put a space after the colon. key: value is a mapping; key:value is a single piece of text.
• Quote text that starts with a special character, such as *, &, !, @, % or a backtick, and text containing : or #.
• Keys must be unique within a mapping. A repeated key is reported as an error rather than silently using the last value.
• For multi-line text, use | to keep line breaks or > to fold lines into one paragraph.

Anchors, Aliases and Merge Keys

YAML can name a block with &name and reuse it with *name; <<: *name merges a reused mapping into another, as Docker Compose files often do with shared settings. JSON has no such references, so the YAML to JSON conversion writes out a full copy at each use. Some files abuse this by nesting aliases so they expand to gigabytes (the "billion laughs" attack); the converter stops such files instead of freezing your browser.

Related Tools

Check and pretty-print the JSON side with the JSON formatter, generate types for it with JSON to TypeScript, or see what changed between two versions of a config file with the diff checker.

Frequently Asked Questions