YAML Validator
Paste YAML and see it validate as you type, with the exact error line and column and a parsed view of the result.
Paste your config and this YAML validator checks it on every keystroke, so you know it’s valid before you ship it to a pipeline or a Kubernetes manifest. When something is off, it tells you the reason and points at the exact line and column — a mis-indented mapping, a stray tab, a duplicate key — instead of a vague failure hours later in CI. When it parses, the right pane shows the parsed structure as JSON, so you can confirm the tool read your nesting the way you meant it. It’s a plain YAML syntax checker and YAML lint that runs entirely in your browser, so nothing you paste leaves the page.
How it works
- 1
Paste your YAML
Drop a config file, a values.yaml, a CI workflow, or any snippet into the left pane. Comments, multi-line lists, and `---` document separators are all read as written.
- 2
Read the live verdict
The status line updates as you type: valid with a document count, or invalid with the reason and the precise line and column, plus a snippet showing the offending spot.
- 3
Check the parsed structure
Once it validates, the right pane shows the parsed data as JSON so you can confirm the indentation nested things the way you intended. Copy that JSON if you need it.
Instant & 100% private — nothing is uploaded
Everything runs locally in your browser. Your code, text and files are processed on your own device and are never sent to a server — so there are no upload waits, no size limits from us, and nothing is ever stored or logged.
Frequently asked questions
- How do I validate YAML online?
- Paste the YAML into the left pane. The tool parses it immediately and shows either “Valid YAML” with the number of documents, or “Invalid YAML” with the reason and the line and column where parsing broke. There’s no button to press — the check runs on every edit.
- Why does the YAML syntax checker flag my indentation?
- YAML is indentation-sensitive and forbids tabs for indentation. If a mapping entry doesn’t line up with its siblings, or you’ve used a tab instead of spaces, the parser stops and reports the line. The snippet under the error puts a caret under the exact column so you can see which space is wrong.
- Does it catch duplicate keys?
- Yes. Two keys with the same name under one mapping are rejected as a duplicate key error, which is a common source of settings that silently get overwritten. This YAML lint surfaces them instead of quietly keeping the last one.
- Can it validate a file with multiple documents?
- It can. Separate documents with `---` and the validator parses each one; the status line reports how many documents it found, and the preview shows them as a JSON array.
- Is my YAML uploaded anywhere?
- No. Parsing happens in your browser with JavaScript. Nothing you paste is sent to a server, which matters when you’re validating configs that contain hostnames, tokens, or other internal details.
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