YAML Formatter & Validator
Beautify and validate YAML with selectable indent and helpful error messages.
Paste any YAML and instantly get a pretty-printed, validated version. Choose 2- or 4-space indent, see error messages with line numbers when parsing fails, and copy the cleaned output. Everything runs locally in your browser via js-yaml.
Common use cases
- Tidy up Kubernetes manifests, Helm values and Docker Compose files
- Validate GitHub Actions and CircleCI workflow files before committing
- Re-indent hand-edited Ansible playbooks and OpenAPI specs
- Catch YAML syntax errors (mixed tabs/spaces, bad indentation) instantly
Frequently asked questions
Does my YAML get uploaded?▾
No — parsing and formatting happen in your browser using js-yaml. Nothing is sent to a server.
Will it preserve comments?▾
No. Standard YAML libraries (including js-yaml) drop comments because they aren't part of the parsed data model. If you need comment-preserving formatting, edit by hand.
What spec does it follow?▾
YAML 1.2 via the js-yaml library, which is widely used in Node.js, Webpack, ESLint and many other tools.
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