YAML Validator & Formatter

What is YAML Validator & Formatter?

Kubernetes manifests, GitHub Actions and docker-compose all use YAML, and YAML's indent sensitivity makes debugging miserable — a single space changes the structure entirely. This tool validates YAML in real time with clear line-numbered errors, re-indents the layout in one click, and converts to JSON so you can inspect the parsed structure. All processing is local.

How to Use

1. Paste YAML content
2. Syntax errors are flagged instantly with line numbers; click to format the layout
3. Switch to YAML -> JSON mode when you need to inspect the structure

FAQ

Does formatting keep comments?

No. Formatting regenerates the document after parsing, so comments are lost — back up before formatting, or use only the error hints to locate problems.

How are YAML and JSON related?

YAML is a superset of JSON — nearly all valid JSON is valid YAML. YAML additionally supports comments, multi-line strings and a terser indentation syntax.

Why does my YAML parse differently than expected?

Common causes: Tab indentation (YAML allows only spaces), a missing space after a colon, and y/n/on/off being parsed as booleans. Switch to YAML -> JSON mode to see the real parse result.

Related Tools