YAML Validator and Linter
Paste YAML and Prettify parses it locally, surfacing indentation slips, bad anchors, and type problems with the line and column where they occur. Multi-document files separated by triple-dashes are supported. Fix the issue and check again with a single keystroke.
What trips up YAML, and how the linter finds it
Most YAML failures come from whitespace: a tab where spaces are expected, a block that is under-indented, or a list item that does not line up with its siblings. The validator reports the first parse error with its line and column, then adds lint warnings for the softer problems it finds.
It also handles the constructs that make YAML tricky, including anchors and aliases and values whose type is ambiguous, so a stray unquoted string that YAML would read as a boolean does not slip through unnoticed.
Multi-document files and type handling
Files that pack several documents into one stream, separated by triple-dash markers, are parsed as a set rather than choking on the separator. A document selector lets you page through each one, which matches how Kubernetes manifests and CI pipelines are usually written.
Scalars are read with a JSON-compatible type model, so numbers, booleans, and null are recognized consistently and you can trust that what validates here maps cleanly onto the data your tools expect.
Runs locally, stays private
The parse happens in your browser, which makes it safe to check a Kubernetes secret template, a deployment manifest, or a CI config full of tokens. None of it is uploaded, so there is no server log of what you validated.
Frequently asked questions
Does the YAML validator cost anything?
No. Validating YAML, linting it, and viewing it in tree, raw, or table form are all free. Pro adds cross-format extras like SQL queries, diff, and schema validation, none of which are required to check syntax.
Is my YAML transmitted to a server?
No. Parsing and linting run locally in the browser, so a manifest or pipeline file with sensitive values never leaves your device to be validated.
Can it handle multi-document YAML?
Yes. Streams that separate documents with triple-dash markers are parsed as multiple documents, and a selector lets you move between them one at a time.
Are comments kept when I reformat or convert?
Validating and viewing do not rewrite your text, but comments are not part of the parsed data model, so reformatting the document or converting it to JSON drops them.