JSON ↔ YAML Converter - Convert Between JSON and YAML

How to use this tool

1. Add input. Paste JSON or YAML into the input panel, or open a local .json, .yaml, or .yml file.
2. Auto-detect or choose. The direction is detected automatically, or you can choose manually.
3. Copy or download output. Copy the converted text or download it as a .json or .yaml file.

JSON vs YAML: what's the difference?

Both formats represent structured data (objects, arrays, strings, numbers, booleans, null), but they have different syntaxes:

• JSON: Strict, machine-friendly. Uses curly braces, square brackets, and double-quoted strings. The de-facto format for APIs.
• YAML: Human-friendly. Uses indentation instead of brackets. Supports comments (#). Common in configuration files (Docker Compose, GitHub Actions, Kubernetes).

YAML is a superset of JSON; all valid JSON is valid YAML, but YAML has many additional features.

When to use each format

• JSON: REST APIs, data interchange, package manifests (package.json)
• YAML: CI/CD pipelines (.github/workflows), Docker Compose, Kubernetes, Ansible, configuration files

YAML gotchas

• Indentation matters: use spaces, never tabs.
• Boolean spellings vary by YAML version: some YAML 1.1 tools treat yes, no, on, and off as booleans. This converter uses YAML 1.2-style boolean values, so those four spellings stay strings; true and false are booleans.
• The Norway problem: YAML 1.1 parsers may read country codes like NO as boolean false. This converter keeps NO as a string, but quoting country codes remains a good choice when sharing YAML with older tools.
• Strings that look like numbers: this converter keeps digit strings with leading zeros, such as 007, as strings so ZIP codes and fixed-width IDs survive conversion. Other YAML tools may apply different numeric rules.
• Date auto-parsing: this converter leaves bare dates such as 2024-01-15 as strings. Some other YAML parsers may turn them into date values, so quote dates when moving configuration between tools with different rules.
• Colons in strings: a colon followed by a space (: ) starts a new mapping key, so such strings must be quoted.

YAML anchors and aliases

YAML supports anchors (&name) and aliases (*name) to reuse content without repetition:

defaults: &defaults
  retries: 3
  timeout: 30

production:
  <<: *defaults
  host: prod.example.com

staging:
  <<: *defaults
  host: staging.example.com

The <<: merge key merges the referenced mapping into the current object. This is widely used in Docker Compose files and CI/CD pipelines to avoid repeating shared configuration. This converter does not expand anchors, aliases, or merge keys; expand them with yq or your editor before converting. Multi-document streams, flow collections, and | or > block scalars are also outside its supported subset and produce a line-numbered error.