Published February 18, 2025 · 6 min read

How to Convert JSON to YAML (and Back)

JSON and YAML are two of the most popular data serialization formats in software development. They represent the same kinds of data structures — objects, arrays, strings, numbers — but with very different syntax philosophies. JSON prioritizes machine readability with strict syntax. YAML prioritizes human readability with clean, indentation-based formatting. Developers constantly need to convert between them.

JSON vs YAML: Key Differences

Both formats can represent the same data, but they look quite different:

JSON example:

{
  "server": {
    "host": "localhost",
    "port": 8080,
    "debug": true,
    "allowed_origins": [
      "https://example.com",
      "https://api.example.com"
    ]
  }
}

YAML equivalent:

server:
  host: localhost
  port: 8080
  debug: true
  allowed_origins:
    - https://example.com
    - https://api.example.com

Key differences at a glance:

• Brackets vs indentation — JSON uses {} and []; YAML uses indentation.
• Quotes — JSON requires quotes around all keys and string values; YAML usually doesn't.
• Comments — YAML supports comments (# like this); JSON does not.
• File size — YAML is typically 15-30% smaller due to less punctuation.
• Parsing — JSON is simpler and faster to parse; YAML parsing is more complex.

When to Use JSON vs YAML

• Use JSON for: APIs, data interchange, package.json, browser-based applications, any context where strict parsing is important.
• Use YAML for: Configuration files (Kubernetes, Docker Compose, GitHub Actions, Ansible), CI/CD pipelines, any file humans edit frequently.

How to Convert JSON to YAML Online

1. Open the JSON to YAML converter.
2. Paste your JSON data or drop a .json file.
3. Get clean, properly indented YAML output instantly.

How to Convert YAML to JSON

Going the other direction is just as easy. Use the YAML to JSON converter when you need to:

• Send configuration data to an API that expects JSON
• Validate YAML by converting to JSON and running through a JSON schema validator
• Use YAML data in a JavaScript application
• Debug YAML indentation issues by seeing the structured JSON output

Common Conversion Gotchas

Converting between JSON and YAML is usually straightforward, but watch out for these edge cases:

• YAML's implicit typing — YAML automatically interprets yes/no as booleans and bare numbers as integers. The string "yes" in JSON becomes the boolean true in YAML unless quoted.
• Multi-line strings — YAML has special syntax for multi-line strings (| for literal, > for folded). These get converted to regular strings with \n in JSON.
• Comments are lost — When converting YAML to JSON, all comments are discarded since JSON doesn't support them.
• Anchors and aliases — YAML supports references (&anchor and *alias) for reusing data. These get expanded into duplicated data in JSON.
• Special values — YAML recognizes .inf, -.inf, and .nan as special float values. JSON doesn't support these natively.

Real-World Use Cases

Kubernetes Configuration

Kubernetes manifests are written in YAML, but kubectl can output JSON. Converting between formats is a daily task for DevOps engineers. Our converter helps you quickly switch between human-editable YAML and machine-readable JSON.

GitHub Actions

GitHub Actions workflows use YAML. If you're generating workflow configurations programmatically from JSON data, you'll need a reliable JSON-to-YAML converter.

Docker Compose

Docker Compose files are YAML. When migrating configuration from a JSON-based system or building compose files from API responses, conversion is essential.

Related Developer Tools

• JSON Formatter — Pretty-print and validate JSON data.
• Minify JSON — Remove whitespace for compact JSON.
• CSV to JSON — Convert spreadsheet data to JSON.
• XML to JSON — Convert XML data to JSON format.

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