YAML Validator
Validate YAML syntax and preview the parsed document as JSON.
YAML Validator
Validate YAML syntax for configuration files, CI pipelines, Docker Compose snippets, Kubernetes manifests, and application settings.
YAML checks
- Parser errors for indentation, mapping, sequence, and scalar mistakes
- Warnings reported by the YAML parser
- JSON preview for valid YAML documents
How to use YAML Validator
The YAML validator checks syntax and previews parsed YAML as JSON. It helps catch indentation problems before a config file reaches deployment.
Developers often use this page when they need yaml checker, yaml validator, yaml linter, and yaml tester.
Privacy and data handling
This tool is designed to run in your browser for normal use, so your input does not need to be sent to a server.
- Input and output stay on the page while you work.
- Copy buttons use your browser clipboard permission when available.
- Avoid pasting private production data on shared or untrusted devices.
Examples
Check YAML indentation
Input
server:
port: 3000Output
Possible issue: port should be indented under serverYAML structure depends on spaces, so indentation errors are common.
Steps
- 1Paste YAML into the input box.
- 2Read any parse error message.
- 3Preview the parsed structure and fix indentation or values.
Common use cases
- Check CI config before committing it.
- Validate Kubernetes or Docker Compose snippets.
- Find indentation mistakes in copied YAML.
Practical tips
- Spaces matter in YAML. Tabs often cause problems.
- Quote strings that look like booleans or dates.
- Check nested lists carefully.
FAQ
Why is YAML indentation important?
Indentation defines structure in YAML. A small spacing change can move a value into a different object or list.
Can YAML be converted to JSON?
Yes. Valid YAML can usually be parsed into a JSON-like structure, though YAML supports some syntax that JSON does not.