YAML Validator

How to Use the YAML Validator

This YAML validator checks YAML data syntax and formats it online. Paste your YAML data into the input field and click "Validate" to check for syntax errors - if found, the error message and line number are displayed. Click "Format" to output valid YAML in a normalized format. It supports key-value pairs, nesting, arrays, strings, numbers, booleans, null, multiline strings (| and >), comments (#), and flow notation ([...] and {...}). Since YAML does not allow tab characters for indentation, an error is shown if tabs are detected.

What is YAML?

YAML (YAML Ain't Markup Language) is a human-readable data serialization format. It is widely used for configuration files (docker-compose.yml, GitHub Actions, Kubernetes manifests, etc.). It is a superset of JSON, using indentation-based structure to represent data. It supports comments and data reuse through anchors and aliases.

Frequently Asked Questions (FAQ)

Q. Can tab characters be used in YAML?

A. No, the YAML specification does not allow tab characters for indentation. Only spaces are permitted. This tool displays an error when tabs are detected.

Q. What YAML syntax is supported?

A. Key-value pairs, nested objects, arrays (- prefix), strings (quoted and unquoted), numbers, booleans, null, multiline strings (| and >), and comments (#) are supported.

Q. Is my input data safe?

A. Yes, it is safe. All processing is completed within your browser, and input data is never sent to any server.