DevsToolkit

YAML Validator

YAML

Validate YAML syntax and get detailed error messages

All processing happens locally in your browser — your data never leaves your machine.
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Examples

Valid Object

Input
name: John Doe
age: 30
email: john@example.com
Output
Valid YAML — parsed as object

Valid Array

Input
- apple
- banana
- cherry
Output
Valid YAML — parsed as array

Invalid YAML

Input
name: John
  invalid indentation
    nested: wrong
Output
Error: bad indentation of a mapping entry

Frequently Asked Questions

What errors does the YAML Validator detect?
The validator detects all YAML syntax errors including incorrect indentation, invalid mappings, duplicate keys, bad escape sequences, and malformed anchors or aliases. It provides the exact line and column where the error occurs.
Does the YAML Validator support multi-document YAML?
The validator checks the first document in a YAML stream using yaml.load(). For multi-document YAML files separated by ---, only the first document is validated. Each document can be validated separately by splitting them.
Is my YAML data sent to a server for validation?
No. All validation runs locally in your browser using JavaScript. Your YAML data never leaves your device, making it safe to validate sensitive configuration files.

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