YAML Validator & Linter

Validate YAML syntax in your browser and catch indentation, duplicate-key and tab errors with line numbers.

Paste YAML:

How to use

Paste your YAML and click Validate. Errors are listed with line numbers; valid YAML shows a parsed JSON preview. Everything runs in your browser.

Is my YAML sent to a server?

No. Parsing and validation happen entirely in your browser.

What does it check?

Indentation errors, tab characters, duplicate keys, malformed key-value lines and nesting mistakes, each reported with a line number.

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Every tool runs 100% in your browser — no uploads, no signups. If a tool saved you time, consider supporting us with a small donation.