YAML Formatter & Linter

Validate, format, and beautify YAML with syntax error detection

Input YAML

Enter YAML

Formatted Output

Formatted YAML will appear here

Format Options

Indent
Line width

Statistics

Lines 0
Chars 0
Keys 0
Depth 0

Examples

What is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialization format commonly used for configuration files and data exchange. Unlike JSON, YAML uses indentation to represent structure, making it easier to read and write for humans.

YAML is widely used in DevOps tools like Kubernetes, Docker Compose, Ansible, and GitHub Actions. Its clean syntax and support for comments make it ideal for configuration management.

Common YAML Syntax Rules

  • Use spaces for indentation (tabs are not allowed)
  • Key-value pairs are separated by a colon and space
  • Lists start with a hyphen and space
  • Strings don't require quotes (unless they contain special characters)
  • Comments start with a hash (#)

Frequently Asked Questions

What is YAML used for?

YAML is primarily used for configuration files in software applications, CI/CD pipelines, container orchestration (Kubernetes), infrastructure as code (Ansible), and data serialization. Its human-readable format makes it popular for DevOps and application configuration.

How do I validate YAML syntax?

Use this free YAML formatter to validate your YAML syntax. Paste your YAML code and click "Format & Validate". The tool will highlight any syntax errors with line numbers, helping you quickly identify and fix issues.

What's the difference between YAML and JSON?

YAML is a superset of JSON, meaning valid JSON is also valid YAML. The main differences are: YAML uses indentation instead of braces, supports comments, is more human-readable, and allows multi-line strings without escaping. JSON is more widely supported in programming languages and APIs.

Why is indentation important in YAML?

YAML uses indentation to represent nested structures and hierarchy. Unlike JSON which uses braces, YAML relies entirely on consistent spacing (typically 2 spaces) to define parent-child relationships. Incorrect indentation is the most common cause of YAML parsing errors.