How yaml validator works
A YAML validator parses your document against a YAML parser and reports either that the document is valid or the first syntax error it hit, with a line number. This catches the common YAML mistakes: inconsistent indentation, a missing space after a colon, a tab used for indentation, or an unbalanced flow collection.
When the document is valid, the tool also re-serializes it as clean, canonical YAML: consistent two-space indentation, dash-prefixed lists, strings quoted only where required, and empty containers as [] and {}. This normalizes messy hand-edited YAML into a stable canonical form you can diff and commit.
Everything runs in your browser using a built-in YAML parser (no external service), so your configuration never leaves your device. Use it to sanity-check a CI pipeline file, a Docker Compose file, or a Kubernetes manifest before you commit it.
Frequently asked questions
What does it mean if my YAML is invalid?
The validator reports the first parse error it encounters, with a line number and a short reason such as bad indentation or expected key. Fix that line and re-validate; sometimes one error masks others further down.
Does it support anchors, aliases and merge keys?
This validator focuses on the common block and flow YAML used in config files (mappings, sequences, quoted strings, block scalars, comments). Advanced features like anchors (&) and aliases (*) are not expanded.
What is the canonical output?
Valid YAML is re-printed with consistent two-space indentation, minimal quoting, and empty containers shown as [] and {}. It is semantically equivalent to your input, just normalized for easy reading and diffing.
Is my data uploaded anywhere?
No. Parsing and re-printing happen entirely in your browser. Nothing is sent to a server.
