Is YAML a superset of JSON?

Yes, valid JSON is valid YAML (since YAML 1.2). You can paste JSON into YAML files. However, YAML has features JSON lacks: comments, anchors/aliases, multi-line strings, and more data types. YAML parsers accept JSON, but JSON parsers reject YAML-specific features.

Why is YAML popular for configuration?

YAML's readability: minimal punctuation, significant whitespace (like Python), comment support, and multi-line strings make configs easy to read and document. JSON's braces and quotes add visual noise. YAML also supports anchors for DRY configurations.

Which is faster to parse, JSON or YAML?

JSON is significantly faster - its simpler grammar allows faster parsing. YAML's flexibility (multiple ways to express the same data) makes parsing complex. For data interchange, especially in performance-critical systems, JSON is preferred. Use YAML for human-edited configs.

YAML vs JSON: When to Use Each Format

YAML vs JSON

Both are data serialization formats, but they serve different purposes best.

Syntax Comparison

JSON:

{
  "server": {
    "host": "localhost",
    "port": 8080,
    "ssl": true
  },
  "databases": ["mysql", "redis"]
}

YAML:

server:
  host: localhost
  port: 8080
  ssl: true
databases:
  - mysql
  - redis

Key Differences

Feature	JSON	YAML

Comments	❌ Not supported	✅ # comments

Readability	Moderate	High

Verbosity	More punctuation	Minimal

Parsing speed	Faster	Slower

Multi-document	❌ No	✅ Yes

When to Use JSON

APIs: Standard for REST APIs
Data exchange: Universal support
JavaScript apps: Native parsing
Performance critical: Faster parsing

When to Use YAML

Configuration files: More readable
Docker Compose: Standard format
Kubernetes: All manifests are YAML
CI/CD pipelines: GitHub Actions, GitLab CI

YAML Superpowers

# Multi-line strings description: | This is a multi-line string that preserves line breaks. # Anchors and aliases (DRY) defaults: &defaults timeout: 30 retries: 3

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