YAML Formatter and Validator
Validate and format YAML online. The tool checks your YAML syntax as you type, reports parse errors, outputs a normalized version with consistent indentation, and offers a JSON view of the same data.
FreeOnline Tool
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How to Use
- Paste or edit your YAML in the input box (a sample is loaded by default)
- The status bar below shows in real time whether the YAML is valid, with a specific error message when it is not
- The "Normalized YAML" tab shows the document re-serialized in a standard, consistent format
- Switch to the "JSON view" tab to inspect the same data as formatted JSON
- Click "Load sample data" to load a complete example with nested mappings and arrays
Features
- Validates YAML syntax in real time and shows the specific parse error when the document is invalid
- Normalized output: re-serializes the parsed document into a standard style with consistent indentation
- JSON view: switch tabs to see the JSON equivalent of the parsed YAML, which makes comparison easy
- Parses YAML mappings, sequences and nested structures
Use Cases
Validating YAML configuration files
Check the syntax of a Kubernetes manifest or CI configuration before you apply it, instead of discovering the error at deploy time.
Standardizing YAML formatting
Reformat inconsistently indented YAML into a uniform style so team collaboration and version diffs stay clean.
Comparing YAML with its JSON shape
Developers who think in JSON can use the JSON view to see exactly what data structure a YAML document produces.
Pinpointing a YAML syntax error
Paste the YAML that is failing and use the error message to locate the offending indentation or syntax quickly.
FAQ
How does the normalized YAML differ from what I typed?
The normalized output is regenerated after parsing, using consistent indentation and formatting rules. The data is identical, but details such as quoting style and indentation width may differ from your original input.
Why does it say my YAML is invalid?
Usually because of inconsistent indentation, a missing space after a colon or some other syntax problem. The error message points to the position and reason, which you can use to fix the document.
How is the JSON view different from a YAML to JSON converter?
The JSON view here is a companion to validation and formatting, meant for checking the structure while you edit. If your goal is to convert and export YAML as JSON, use the dedicated YAML to JSON converter on this site.
Is my data uploaded to a server?
No. All validation and formatting is computed in your browser and nothing is uploaded.