JSON to YAML Converter

YAML is the language of modern configuration: Kubernetes manifests, Docker Compose, GitHub Actions, GitLab CI, Ansible and OpenAPI specs. It is easier to read and comment than JSON, and every JSON document is also valid YAML data. This converter produces idiomatic YAML with two-space indentation, preserves key order and quotes only what needs quoting.

1. Paste JSON or drop a .json file.
2. The YAML appears instantly; key order is preserved.
3. Check values that were quoted — they would otherwise change type in YAML.
4. Copy the YAML or download a .yaml file.

Example

{
  "services": {
    "web": {
      "image": "nginx:1.27",
      "ports": ["8080:80"],
      "environment": { "MODE": "production", "DEBUG": "false", "COUNTRY": "NO" }
    }
  }
}

services:
  web:
    image: nginx:1.27
    ports:
      - '8080:80'
    environment:
      MODE: production
      DEBUG: 'false'
      COUNTRY: 'NO'

Strings like "false" and "NO" are quoted in the YAML output. Left unquoted, many YAML parsers would read them as the boolean false — the infamous "Norway problem" where the country code NO turns into false.

How values are written

• Strings are written plain whenever possible and quoted when they would otherwise be misread: 'true', '02134', '1.0', values starting with special characters, or containing : or #.
• Numbers, booleans and null keep their JSON types.
• Objects become indented mappings; arrays become lists with - markers.
• Multi-line strings are preserved exactly.

Where YAML is used

Kubernetes and Helm, Docker Compose, GitHub Actions and GitLab CI pipelines, Ansible playbooks, OpenAPI/Swagger definitions, Home Assistant, static site generators such as Jekyll and Hugo front matter, and countless application config files. Converting from JSON is a quick way to start one of these files from an API response or generated data.

Adding comments after conversion

JSON has no comments, so the generated YAML has none either. One of the main reasons to switch to YAML is that you can now document your configuration with # comments.

Real-world examples

Write a Docker Compose file from JSON

Some tools export settings as JSON, while Docker Compose, Kubernetes and GitHub Actions expect YAML. Converting avoids retyping and indentation mistakes, and values such as 8080:80 are quoted where YAML needs it.

{
  "services": {
    "web": {
      "image": "nginx:1.27",
      "ports": ["8080:80"],
      "restart": "unless-stopped"
    }
  }
}

services:
  web:
    image: nginx:1.27
    ports:
      - '8080:80'
    restart: unless-stopped

Make an API response readable

YAML drops braces and quotes, so a deeply nested API response becomes much easier to read and to paste into documentation or a support ticket.

{"user":{"id":7,"name":"Sam","roles":["editor","billing"],"active":true,"zip":"02134"}}

user:
  id: 7
  name: Sam
  roles:
    - editor
    - billing
  active: true
  zip: '02134'

Common errors and how to fix them

Related guides

• JSON Lines (JSONL) explained

Convert JSON to YAML in code

For one-off files the tool above is quickest. To automate the same task in a script or pipeline, these snippets are a good starting point.

Python (PyYAML)

import json
import yaml  # pip install pyyaml

with open("data.json", encoding="utf-8") as f:
    data = json.load(f)

print(yaml.safe_dump(data, sort_keys=False, allow_unicode=True))

Command line (yq)

# mikefarah/yq v4
yq -p json -o yaml '.' data.json > data.yaml

Node.js (js-yaml)

import yaml from "js-yaml";  // npm install js-yaml
const out = yaml.dump(JSON.parse(text), { noRefs: true });

Frequently asked questions

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