YAML Formatter & Validator
Validate YAML and reformat it with consistent indentation and normalized quoting. Reports parse errors with the exact line and column. Runs in your browser.
YAML formatter and validator
YAML is whitespace-sensitive, which makes it both compact and unforgiving — a single stray space or an inconsistent indent can turn a valid file into a parse error. This tool is both a YAML validator and a YAML formatter: it parses your input to confirm it is well-formed, then re-emits it with clean, consistent indentation and normalized quoting. If the YAML is invalid, it tells you exactly where the problem is. Everything runs in your browser, so configuration files and secrets never leave your device.
Validate YAML with precise errors
As soon as you paste YAML, the validator parses it using a battle-tested YAML library. If the document is well-formed, you get a green confirmation; if it is not, the tool reports the parser's reason along with the exact line and column where parsing failed. That line-and-column detail is what makes fixing real configuration files fast — instead of hunting through a large file, you go straight to the offending mapping entry, bad indentation, or unclosed quote.
Reformat and beautify YAML
When the input is valid, the formatter rewrites it with uniform indentation that you choose — two or four spaces — expands inline flow collections such as [a, b] and {key: value} into clean block style, and normalizes quoting so the file reads consistently. An optional sort keys toggle alphabetizes mapping keys, which is handy for producing stable, diff-friendly config files. Multi-document streams separated by --- are fully supported, so Kubernetes manifests and other bundled documents reformat correctly as a set.
How to use it
Paste your YAML into the input box. The validation banner updates live to tell you whether the document is valid. Adjust the indent size or enable sort-keys if you want, then read the cleaned-up YAML in the output panel and click Copy. There is no upload and no account required.
Common uses
A YAML formatter and validator is most useful for the files developers touch every day: CI pipeline definitions, Docker Compose files, Kubernetes manifests, Ansible playbooks, and application config. Validating before you commit catches the indentation mistakes that would otherwise fail a build or a deploy. Reformatting also pays off in code review, because normalized indentation and key order turn noisy, hard-to-read diffs into changes a reviewer can actually follow, and it removes the small style inconsistencies that creep in when several people edit the same file by hand.
Related developer tools
YAML and JSON describe the same kinds of data, so the JSON Formatter is a natural companion. For markup and stylesheets, see the XML Formatter and HTML Formatter.
YAML formatter and validator
YAML is whitespace-sensitive, which makes it both compact and unforgiving — a single stray space or an inconsistent indent can turn a valid file into a parse error. This tool is both a YAML validator and a YAML formatter: it parses your input to confirm it is well-formed, then re-emits it with clean, consistent indentation and normalized quoting. If the YAML is invalid, it tells you exactly where the problem is. Everything runs in your browser, so configuration files and secrets never leave your device.
Validate YAML with precise errors
As soon as you paste YAML, the validator parses it using a battle-tested YAML library. If the document is well-formed, you get a green confirmation; if it is not, the tool reports the parser's reason along with the exact line and column where parsing failed. That line-and-column detail is what makes fixing real configuration files fast — instead of hunting through a large file, you go straight to the offending mapping entry, bad indentation, or unclosed quote.
Reformat and beautify YAML
When the input is valid, the formatter rewrites it with uniform indentation that you choose — two or four spaces — expands inline flow collections such as [a, b] and {key: value} into clean block style, and normalizes quoting so the file reads consistently. An optional sort keys toggle alphabetizes mapping keys, which is handy for producing stable, diff-friendly config files. Multi-document streams separated by --- are fully supported, so Kubernetes manifests and other bundled documents reformat correctly as a set.
How to use it
Paste your YAML into the input box. The validation banner updates live to tell you whether the document is valid. Adjust the indent size or enable sort-keys if you want, then read the cleaned-up YAML in the output panel and click Copy. There is no upload and no account required.
Common uses
A YAML formatter and validator is most useful for the files developers touch every day: CI pipeline definitions, Docker Compose files, Kubernetes manifests, Ansible playbooks, and application config. Validating before you commit catches the indentation mistakes that would otherwise fail a build or a deploy. Reformatting also pays off in code review, because normalized indentation and key order turn noisy, hard-to-read diffs into changes a reviewer can actually follow, and it removes the small style inconsistencies that creep in when several people edit the same file by hand.
Related developer tools
YAML and JSON describe the same kinds of data, so the JSON Formatter is a natural companion. For markup and stylesheets, see the XML Formatter and HTML Formatter.
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Frequently Asked Questions
Common questions about the YAML Formatter & Validator
Yes. It is both a YAML validator and a formatter. It parses your input to confirm it is well-formed and shows a clear valid or invalid status. When the YAML is valid it reformats it; when it is invalid it reports the error.
When parsing fails, the tool shows the parser's reason for the failure together with the exact line and column number where it occurred, so you can jump straight to the problem instead of scanning the whole file.
Yes. Documents separated by the --- marker, such as bundled Kubernetes manifests, are each parsed and reformatted, then re-joined, so multi-document streams are handled correctly.
Yes. You can choose two-space or four-space indentation, and an optional sort-keys toggle alphabetizes mapping keys to produce stable, diff-friendly output.
No. All validation and formatting happens locally in your browser. Your YAML, including any configuration or secrets, never leaves your device.
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ℹ️ Disclaimer
This tool is provided for informational and educational purposes only. All processing happens entirely in your browser - no data is sent to or stored on our servers. While we strive for accuracy, we make no warranties about the completeness or reliability of results. Use at your own discretion.