JSON vs YAML: When to Use Each and How to Convert

JSON and YAML both represent structured data, but they serve different ecosystems. Here is when to use each and how to convert between them.

Side-by-Side

JSON:

{
  "server": {
    "host": "0.0.0.0",
    "port": 3000,
    "features": ["cors", "compression"]
  }
}

YAML:

server:
  host: "0.0.0.0"
  port: 3000
  features:
    - cors
    - compression

When to Use Each

Use Case	JSON	YAML
API responses	Yes	No
Kubernetes configs	No	Yes
Docker Compose	No	Yes
package.json	Yes	No
CI/CD pipelines	No	Yes

YAML Gotchas

The Norway Problem

norway: NO    # Boolean false, not string 'NO'!
country: "NO" # String 'NO'

Type Coercion

version: 1.0     # float, not string
phone: [phone]   # octal number!
time: 12:30      # sexagesimal (750)

Fix: Always quote values that should be strings.

Security Warning

# NEVER do this!
yaml.load(user_data)  # Can execute code!

# ALWAYS use safe_load
yaml.safe_load(user_data)

Try It Online

Convert JSON to YAML with DevToolBox Converter - bidirectional, syntax highlighting.

---

JSON or YAML for configs? Comment below!