JSON vs YAML: what’s the difference?

Both JSON and YAML are used to represent structured data. JSON is strict and universal; YAML is more human-friendly but easier to get wrong.

Quick comparison

• Best for machines: JSON
• Best for humans editing configs: YAML (carefully)
• Strictness: JSON is strict; YAML has more “magic” and implicit typing
• Comments: YAML supports comments; JSON does not (by default)

Example: same data

JSON:

{
  "service": "api",
  "port": 8080,
  "enabled": true,
  "tags": ["prod", "us-east-1"]
}

YAML:

service: api
port: 8080
enabled: true
tags:
  - prod
  - us-east-1

Common YAML pitfalls

• Indentation: spaces matter; inconsistent indentation breaks parsing.
• Implicit types: strings like on, off, or dates can be interpreted unexpectedly by some parsers.
• Tabs: many YAML parsers reject tabs.

When to choose JSON

• APIs and network payloads
• Interoperability across languages and systems
• When you want strict validation and predictable parsing

When to choose YAML

• Configuration files edited by humans
• When comments are important
• When readability matters more than strictness

Related: Validate JSON · Pretty print JSON