How do I validate YAML?

Paste your text above. If parsing succeeds, you see Valid YAML; otherwise you see the error details.

Why is my YAML invalid?

Common causes include inconsistent indentation, tabs mixed with spaces, and misaligned list items under a key.

Children must indent further than their parent, siblings must align, and list dashes must line up consistently.

Yes. This free validator works in your browser with no account and no install.

Paste the document here to parse it. Pair the result with a quick visual scan of indentation for nested maps and lists.

A free online tool that checks whether text is valid YAML for students and developers.

It parses your text with a YAML library in the browser and maps failures to line and column hints when available.

Paste YAML, optionally load a valid or broken example, and read the status panel.

Yes. It is free with no sign-up.

Yes. Mobile browsers are supported.

Free YAML Validator Online, Check Syntax Fast | Binary Tech