YAML Tools
YAML Schema Validator
Validate YAML data against a JSON Schema.
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What is YAML Schema?
A schema validator for YAML: define a JSON Schema in the right pane and validate any YAML document against it, seeing every failed path.
How it works
Both panes parse with js-yaml; the schema is compiled with AJV and the data is validated, listing each error's JSON path and message.
- Enter your input. Type or paste your input into the field above — the tool responds instantly.
- Review the result. Output updates live as you type. Everything runs entirely in your browser.
- Copy or download. Use the Copy button to grab the result, or Download to save it as a file.
Examples
Contract checking
Validate a YAML document against a JSON Schema — required fields, types, and formats checked with a clear error report.
Common mistakes
YAML type coercion surprises
An unquoted version number like 1.0 becomes a float. The validator catches type mismatches that cause runtime surprises.
Frequently asked questions
Which schema features are supported?
Draft-07 core: required, types, enums, formats, nested objects, arrays, and references.
Can I paste a schema and data separately?
Yes — schema in one box, document in the other, with the error list grouped by path.