YAML Formatter & Validator
Validate and format YAML configs in the browser with clear parser errors and copy-ready output.
Input
Paste YAML to validate and format
Output
Formatted YAML output
Paste YAML, then choose Format YAML.
How to validate YAML
Paste YAML into the input panel and choose Format YAML. The parser checks indentation, mappings, sequences, and scalar syntax locally before producing normalized two-space output.
Common YAML mistakes
- Indented children must align consistently under the same parent.
- Tabs are unsafe in YAML indentation; use spaces.
- Colons in unquoted values can be interpreted as mappings.
- Lists require consistent
-indentation.
What this YAML Formatter does
Use this YAML formatter and validator to check indentation-sensitive YAML and produce consistent two-space formatted output. It is useful for config files, CI snippets, Docker Compose examples, and infrastructure manifests.
When developers use it
- Validate YAML syntax before pasting it into GitHub Actions, Kubernetes, Docker Compose, or app config files.
- Reformat YAML mappings and sequences for easier review.
- Catch indentation and mapping errors with line and column feedback.
Privacy, input, and output
YAML validation and formatting happen in your browser tab. PayloadHarbor does not upload YAML files or snippets.
Paste YAML into the input panel and choose Format YAML. Valid YAML is parsed and emitted with consistent indentation; parser errors keep the output empty.
Validation rules and limitations
- The formatter checks YAML syntax, not Kubernetes, Compose, or CI schema rules.
- Comments may not be preserved after parsing and re-stringifying YAML.