Online YAML Validator — Check Syntax with Line Numbers
Paste YAML and see live syntax validation with line and column errors. YAML 1.2 parsing runs entirely in your browser — ideal before formatting configs or committing manifests.
Developer notes
• Validation runs automatically after you pause typing (debounced) — no server round-trip. • Parsing uses js-yaml in YAML 1.2 core mode; `yes`, `no`, `on`, and `off` stay strings. • The results panel shows Valid/Invalid, document count, and the failing document index when a `---` stream breaks. • This page checks syntax only — use Beautify YAML to format, not to convert to JSON.
Options that change the verdict
When teams pick this route
• Gate CI or GitOps YAML before it lands in a repo. • Confirm exports from converters still parse as YAML 1.2. • Debug copy-paste accidents in support tickets with precise line numbers. • Quick check before prettifying with Beautify YAML.
Related formatting tools
Format valid YAML with Beautify YAML, minify with Minify YAML, or convert via YAML → JSON on the conversion hub.
YAML validator FAQ
Syntax checking without leaving your browser
Does this beautify or minify YAML?
No — this route validates syntax only. Use Beautify YAML to indent configs or Minify YAML to compress them.
Is YAML 1.1 supported?
The page parses YAML 1.2. A %YAML 1.1 directive does not turn yes/no/on/off into booleans.
Is my YAML uploaded?
Never — parsing and validation stay entirely inside your browser tab.
Multiple documents separated by ---?
Yes — the results panel shows how many documents are in the stream and which document failed when syntax breaks.
Schema or Kubernetes validation?
This tool checks YAML syntax only. It does not validate Kubernetes, OpenAPI, or custom schemas.
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