What YAML version is supported?

The validator uses js-yaml which supports YAML 1.2. It handles all standard YAML features including anchors (&), aliases (*), and merge keys (<<).

Does it fix YAML errors automatically?

No. YAML errors require human judgement to fix correctly. The tool reports the error location and type so you can make the right correction.

What are the most common YAML errors?

Inconsistent indentation (mixing tabs and spaces), missing colons after keys, unquoted strings containing special characters (:, #, [, {), and improper multi-line string syntax are the most common issues.

Can I reformat valid YAML?

Yes. After successful validation, click "Format YAML" to re-indent the document with consistent 2-space indentation and normalise the structure.

YAML Validator

Validates YAML syntax and reports errors with line and column numbers. On success, shows the parsed structure and optionally re-formats the YAML with consistent indentation. Uses the js-yaml parser for strict YAML 1.2 compliance. Useful for validating Kubernetes configs, GitHub Actions, Docker Compose, and Ansible playbooks.

Runs entirely in your browser — your input is never uploaded, stored, or logged.

Paste your YAML and instantly see whether it's valid — errors are shown with precise locations. To convert valid YAML to JSON, use the YAML to JSON converter.

Examples

Valid YAML

Input

name: app
version: 1.0

Output

Valid YAML ✓

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