YAML Formatter

YAML Formatter - Format and Beautify YAML Online

A powerful online YAML formatter and beautifier tool that helps you format, beautify, and minify YAML code. Features syntax highlighting and customizable indentation. Perfect for developers, DevOps engineers, and anyone working with YAML configuration files.

What is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialization language. It's commonly used for:

- Configuration files (Docker, Kubernetes, CI/CD)
- Data exchange between programming languages
- Application settings and preferences
- Infrastructure as Code (Ansible, Terraform)
- API specifications (OpenAPI/Swagger)
- Static site generators (Jekyll, Hugo)

YAML is designed to be easy to read and write. It uses indentation (spaces, not tabs) to represent structure and supports:
- Key-value pairs
- Lists (arrays)
- Nested structures
- Multiple data types (strings, numbers, booleans)
- Comments with #
- Multi-line strings

What does this YAML Formatter do?

This tool provides two main functions:

1. Format (Beautify): Takes poorly formatted YAML and makes it readable with proper indentation and spacing. You can choose indent size (2, 4, or 8 spaces) and optionally preserve or remove comments.

2. Minify: Removes unnecessary whitespace and blank lines to create a more compact YAML file. Optionally removes comments. Useful for reducing file size while maintaining readability.

Note: YAML relies on indentation for structure, so minification has limits. Unlike JSON or XML, you can't remove all whitespace. This tool optimizes YAML while keeping it valid.

Both functions include syntax highlighting for keys, values, comments, and special characters.

How do I format YAML?

Formatting YAML is simple:

1. Paste or type your YAML code in the input field
2. Select your preferred indent size (2, 4, or 8 spaces)
3. Optionally check/uncheck 'Preserve comments'
4. Click the 'Format' button
5. View the beautifully formatted YAML in the output section

The formatted YAML will have:
- Consistent indentation throughout
- Proper spacing for readability
- Syntax highlighting for keys, values, and comments
- Easy to read structure

Note: YAML uses spaces for indentation, never tabs. This formatter automatically uses spaces.

Why is YAML indentation important?

In YAML, indentation is not just for readability - it defines the structure and nesting of data:

Correct indentation:
parent:
child1: value1
child2: value2

Incorrect indentation (syntax error):
parent:
child1: value1
child2: value2

Key rules:
- Use spaces only, never tabs
- Be consistent (use same indent size throughout)
- Child elements must be indented more than parent
- Items at same level must have same indentation

Mixing tabs and spaces or inconsistent indentation will cause parsing errors. This formatter ensures consistent spacing throughout your YAML.

What does 'Preserve comments' mean?

The 'Preserve comments' option controls whether YAML comments are kept or removed:

With preserve comments (checked):
# Database configuration
db:
host: localhost # Server address
port: 5432

Without preserve comments (unchecked):
db:
host: localhost
port: 5432

When to preserve:
- During development and debugging
- When comments contain important documentation
- For configuration files that need explanation

When to remove:
- To reduce file size slightly
- For cleaner output
- When comments are temporary notes

Note: YAML comments start with # and continue to end of line.

YAML vs JSON - which should I use?

YAML and JSON serve similar purposes but have different strengths:

YAML advantages:
- More human-readable and writable
- Supports comments
- Less verbose (no quotes, braces, commas required)
- Better for configuration files
- Supports complex data types
- Multi-line strings are easier

JSON advantages:
- Simpler syntax (easier to parse)
- Better browser/JavaScript support
- Faster to parse
- Stricter rules (less ambiguity)
- Better for APIs and data exchange
- Smaller file size when minified

Use YAML for:
- Configuration files (Docker, Kubernetes, CI/CD)
- Human-edited files
- Documentation that needs comments

Use JSON for:
- API responses and requests
- JavaScript applications
- Data that's rarely manually edited
- When parsing performance matters

Common YAML mistakes and how to avoid them

Common YAML syntax issues:

1. Using tabs instead of spaces:
Wrong: [tab]key: value
Right: [2 spaces]key: value

2. Inconsistent indentation:
Wrong:
parent:
child1: value
child2: value
Right:
parent:
child1: value
child2: value

3. Missing space after colon:
Wrong: key:value
Right: key: value

4. Incorrect list syntax:
Wrong:
items:
- item1
- item2
Right:
items:
- item1
- item2

5. Unquoted special strings:
Wrong: value: yes # Parsed as boolean
Right: value: "yes" # Parsed as string

This formatter helps you maintain consistent indentation and proper YAML structure.

Is my YAML data safe?

Yes, your data is completely safe and private. This tool:

- Processes all YAML entirely in your browser
- Does not send any data to our servers
- Does not store or log any of your YAML
- Works offline once the page is loaded
- Does not use any external services

You can even disconnect from the internet after loading the page and the tool will still work perfectly. Your YAML data never leaves your computer. This makes it safe to format sensitive configuration files.

Key Features

• Format YAML with customizable indentation (2, 4, or 8 spaces)
• Minify YAML to reduce file size
• Preserve or remove comments option
• Syntax highlighting for keys, values, booleans, numbers, and comments
• Real-time statistics (characters, lines, size)
• Copy formatted YAML to clipboard
• Download formatted YAML as .yaml file
• Upload YAML files for formatting
• Dark mode support
• No file size limits
• 100% client-side processing - your data never leaves your browser
• Works offline after initial load
• Mobile-friendly responsive design
• Ensures spaces-only indentation (no tabs)