YAML Validator
Validate YAML syntax and structure.
Validate YAML syntax and structure.
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Tool guide
Free Online YAML Validator
Check whether one YAML document can be parsed by the installed YAML library. This syntax-focused validator reports parser errors in the browser, but it does not verify Kubernetes, OpenAPI, workflow, or other application-specific schemas.
Steps
How it works
- Paste YAML or choose one YAML, YML, or TXT file.
- Run the parser-based YAML syntax check.
- Review the success result or the YAML library's error details.
- Copy or download a successful validation result if needed.
Highlights
Key features
- Validates YAML by attempting a single-document parse.
- Uses YAML library error messages for malformed input.
- Detects parser-level issues, including duplicate mapping keys when rejected by the library.
- Works with pasted content and supported YAML, YML, or TXT files.
- Does not rewrite the source during validation.
Use cases
Common uses
- Check YAML configuration syntax before committing it.
- Find indentation or mapping mistakes in a YAML document.
- Verify that a YAML snippet can be parsed into data.
- Inspect parser feedback while debugging configuration files.
Notes
Limitations to know
- This is syntax parsing, not schema or semantic validation.
- Kubernetes, Docker Compose, GitHub Actions, OpenAPI, and other product-specific rules are not checked.
- Only one YAML document is parsed; multi-document streams are not supported by this operation.
- Error locations and wording depend on the YAML library and are not presented as a separate structured line-and-column report.
- Support follows the installed YAML library defaults and is not a guarantee for every YAML version, tag, or custom schema.
FAQ
Frequently asked questions
Does this validate Kubernetes YAML?
It checks YAML syntax only. It does not validate Kubernetes resource kinds, fields, or cluster-specific rules.
Does it detect duplicate keys?
Duplicate mapping keys are reported when the installed YAML parser rejects them under its current defaults.
Does it show line and column errors?
The YAML library's error message may include location details, but the tool does not generate a separate structured location report.
Are multiple YAML documents supported?
No. The validator currently uses a single-document parse operation.
Are anchors and aliases valid?
Supported YAML anchors and aliases can parse, subject to the library's rules and alias handling.
Can syntactically valid YAML still be incorrect?
Yes. Valid syntax does not confirm that values or fields meet the requirements of an application or schema.