YAML Formatter & Beautifier - Format YAML Online

Format and beautify YAML configuration files online. Proper indentation, consistent structure, and validation help you maintain clean, readable YAML—essential for DevOps, Kubernetes, Docker, and modern application configuration.

What Is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialization format commonly used for configuration files. It's popular because it's easier to read and write than JSON or XML, using indentation instead of brackets or tags.

YAML is used extensively in:

• Kubernetes manifests
• Docker Compose files
• CI/CD pipelines (GitHub Actions, GitLab CI)
• Ansible playbooks
• Application configuration

How to Use

1. Paste your YAML - Enter messy or unformatted YAML
2. Click "Format" - Beautify with proper indentation
3. Validate - Check for syntax errors
4. Copy or download - Use the cleaned YAML

Key Features

• Instant formatting - Beautify YAML in one click
• Syntax validation - Detect errors before deployment
• Consistent indentation - Choose 2 or 4 spaces
• Preserve comments - Keep your documentation
• Real-time preview - See results immediately
• No data storage - Your configs stay private

YAML Formatting Rules

Indentation

YAML uses spaces (not tabs) for structure:

parent:
  child: value
  nested:
    deep: value

Key-Value Pairs

Simple assignments:

name: my-application
version: 1.0.0
enabled: true

Lists

Collections of items:

items:
  - first
  - second
  - third

Nested Structures

Complex configurations:

database:
  host: localhost
  port: 5432
  credentials:
    username: admin
    password: secret

Use Cases

DevOps & Cloud

• Kubernetes manifests - Pod, Service, Deployment configs
• Docker Compose - Multi-container definitions
• Terraform variables - Infrastructure as code
• Ansible playbooks - Automation scripts

CI/CD Pipelines

• GitHub Actions - Workflow definitions
• GitLab CI/CD - Pipeline configurations
• CircleCI - Build configurations
• Azure Pipelines - Pipeline YAML

Application Configuration

• Spring Boot - application.yml files
• Ruby on Rails - config/database.yml
• Python Flask/Django - Configuration files
• Node.js - Various config formats

Infrastructure

• Helm Charts - Kubernetes package values
• CloudFormation - AWS infrastructure
• Serverless Framework - Lambda configurations
• Pulumi - Infrastructure definitions

Common YAML Mistakes

Quoting in YAML

When to quote strings:

# These need quotes
message: "Contains: colon"
hash: "#looks like comment"
json: "[1, 2, 3]"
number_string: "123"  # Preserve as string

# These don't need quotes
simple: just text here
path: /usr/local/bin
version: 1.2.3

Multi-line Strings

Literal Block (preserves newlines)

description: |
  This is line one.
  This is line two.
  Newlines are preserved.

Folded Block (joins lines)

description: >
  This is a long paragraph
  that will be joined
  into a single line.

Frequently Asked Questions

What's the difference between YAML and JSON?

YAML is a superset of JSON—valid JSON is valid YAML. YAML is more readable with indentation-based structure, while JSON uses explicit brackets and braces.

Tabs vs. spaces: What should I use?

Always use spaces! YAML does not allow tabs for indentation. Most editors can be configured to insert spaces when you press Tab.

How many spaces for indentation?

2 spaces is most common (Kubernetes standard), but 4 spaces also works. Be consistent within your file.

Why does my YAML fail to parse?

Common causes:

• Tab characters (use spaces)
• Inconsistent indentation levels
• Unquoted special characters
• Missing colons or spaces after colons

Can I include comments in YAML?

Yes! Lines starting with # are comments:

# This is a comment
key: value  # Inline comment

How do I represent null/empty values?

empty: null
also_empty: ~
blank:

YAML vs. JSON Comparison