What YAML version does this support?

The validator uses the js-yaml library, which supports YAML 1.2 — the most widely used version, covering anchors, aliases, multi-line strings, and all core scalar types.

Does it modify my YAML?

No. The validator only parses your input to check for errors. It does not reformat, sort keys, or alter your YAML in any way.

Why does it show the result as JSON?

JSON is a human-readable, language-agnostic representation of the parsed data structure. It lets you quickly confirm that your YAML parsed to the exact values you intended.

Is my YAML sent to a server?

No. Validation runs entirely in your browser using js-yaml. Nothing is transmitted anywhere.

YAML VALIDATOR

Check YAML syntax instantly and preview the parsed structure as JSON. Nothing is uploaded to any server.

YAML Input

Result

Click Validate to check your YAML

How to validate YAML

1
Paste your YAML into the input box.
2
Click Validate to check the syntax.
3
If valid, the parsed structure appears as formatted JSON on the right.
4
If invalid, the exact error message and line number are displayed.

Questions

What YAML version does this support?: The validator uses the js-yaml library, which supports YAML 1.2 — the most widely used version, covering anchors, aliases, multi-line strings, and all core scalar types.
Does it modify my YAML?: No. The validator only parses your input to check for errors. It does not reformat, sort keys, or alter your YAML in any way.
Why does it show the result as JSON?: JSON is a human-readable, language-agnostic representation of the parsed data structure. It lets you quickly confirm that your YAML parsed to the exact values you intended.
Is my YAML sent to a server?: No. Validation runs entirely in your browser using js-yaml. Nothing is transmitted anywhere.