YAML Formatter & Validator
Format, validate, and optimize YAML files with error detection online
Clean up and validate your YAML files with our comprehensive formatting tool. Automatically detects syntax errors and properly formats indentation for better readability. Perfect for Kubernetes, Docker, Ansible configurations, and more.
Input YAML
Validation Result
Format or validate your YAML to see results
YAML Validation vs. Formatting
YAML Validation
Validation checks if your YAML content follows the correct syntax rules without attempting to modify it. It detects errors like:
- Invalid indentation
- Unmatched quotes
- Improper list formatting
- Duplicate keys
- Tab character usage
- Invalid escape sequences
YAML Formatting
Formatting restructures your YAML content to follow consistent style rules while preserving the data structure:
- Standardizes indentation (usually 2 spaces)
- Aligns elements properly
- Organizes lists consistently
- Can optionally sort keys alphabetically
- Removes unnecessary quotes
- Normalizes document structure
Common YAML Errors & Solutions
Indentation Errors
Unquoted Special Characters
What is YAML?
YAML (YAML Ain‘t Markup Language) is a human-readable data serialization format. It‘s commonly used for configuration files and in applications where data is being stored or transmitted.
YAML is designed to be easily readable by humans, and is often used in place of JSON or XML for configuration files. Its key features include:
- Clean, minimal syntax with significant whitespace
- Support for complex data structures
- Comments using the # symbol
- Ability to reference other parts of the document
- Support for multiple documents in a single file
YAML Lint Functionality
Our YAML validator includes comprehensive linting functionality that goes beyond basic syntax checking:
Syntax Validation
- Detects malformed YAML structures
- Identifies inconsistent indentation
- Finds unclosed quotes and brackets
- Checks for invalid escape sequences
- Verifies proper list formatting
Semantic Analysis
- Identifies duplicate keys
- Warns about potential type mismatches
- Detects inconsistent key naming styles
- Checks for unnecessary quotes
- Warns about excessively long lines
When to Use YAML Linting
YAML linting is especially important before:
- Deploying Kubernetes manifests
- Committing configuration files to version control
- Running Ansible playbooks
- Starting Docker Compose services
- Executing CI/CD workflows
- Applying infrastructure as code changes