📚 About YAML Formatting & Validation
Master YAML syntax, structure, and best practices with comprehensive guides
What is YAML?
YAML (YAML Ain't Markup Language) is a human-friendly data serialization format designed to be easily readable and writable by humans while maintaining compatibility with most programming languages.
Key characteristics:
- Human-readable: Clean, minimal syntax
- Whitespace-sensitive: Indentation defines structure
- Language-independent: Works with all major languages
- Easy to parse: Simple for both humans and machines
- Supports complex data: Lists, maps, scalars, and more
YAML Data Types
Supported data types:
- Scalars: Strings, integers, floats, booleans, null
- Lists: Ordered collections with
-prefix - Maps: Key-value pairs with
key: value - Nested structures: Combine lists and maps
- Quoted strings: Single or double quotes
- Multi-line strings: Literal
|or folded>
Tool Features
- Validate YAML syntax
- Format with proper indentation
- Detect syntax errors
- Show detailed error messages
- Line numbers for debugging
- Copy and clear functionality
- 100% browser-based processing
Common Use Cases
- Configuration Files: Kubernetes, Ansible, Docker Compose
- CI/CD Pipelines: GitHub Actions, GitLab CI
- Infrastructure: IaC tools like Terraform
- Application Settings: Spring Boot, Python apps
- Data Serialization: Replacing JSON/XML
- Documentation: API specs, metadata
How to Use This Tool
✓ To Validate YAML:
- Paste your YAML in the input area
- Click the Validate button
- Check if syntax is valid
- See error messages if any issues found
✨ To Format YAML:
- Paste your YAML in the input area
- Click the Format button
- Get properly indented YAML
- Copy the formatted result
YAML Syntax Basics
Lists (arrays):
- apple
- banana
- orange
Maps (objects):
name: John
age: 30
city: New York
YAML Best Practices
- Use 2-space indentation: Standard in YAML
- Never use tabs: Only spaces allowed
- Keep consistent: Same indentation throughout
- Quote strings with special chars: Use quotes wisely
- Avoid complex nesting: Keep it readable
- Use comments liberally: Document complex sections
Common Issues & Solutions
❌ Indentation Errors
Solution: YAML is whitespace-sensitive. Use exactly 2 spaces per indentation level. Never use tabs.
❌ Unexpected Mapping
Solution: Missing quotes around values containing colons. Quote strings like "key: value".
❌ Tab Characters
Solution: Tabs are not allowed in YAML. Replace all tabs with spaces.
❌ Incorrect List Format
Solution: Use - prefix with space for list items, not commas.
Advanced YAML Features
Anchors & Aliases: Reuse content with &anchor and *alias
Multi-line Strings:
|- Literal (preserves newlines)>- Folded (folds newlines)
Special Values:
~- Null/Nonetrue/false- Booleans.inf, -.inf, .nan- Special floats
Real-world Example
Docker Compose Configuration:
services:
web:
image: nginx
ports:
- "80:80"
db:
image: postgres
environment:
POSTGRES_DB: myapp