YAML Validator
Check YAML syntax and pinpoint the exact error.
Processed locally in your browser. Nothing you enter is uploaded or stored.
- Parses with the same YAML library the YAML ↔ JSON converters on this site use, so "valid here" means it will actually convert.
- Points at the exact line and column of the first error — YAML's indentation-sensitivity makes this especially hard to spot by eye.
- Runs in your browser; config isn't uploaded.
Why this is private
- Processed locally in your browser. Nothing you enter is uploaded or stored.
- Open your browser's DevTools → Network tab while using this tool — you won't see a request carrying your input, because it never leaves your device.
- Nothing you enter is uploaded to a server or shared with us — the processing happens entirely on your device.
Overview
Checks whether YAML is syntactically valid — indentation, anchors, block/flow structure — and reports the exact line and column of the first error.
How to use it
- 1Paste YAML.
- 2Validation runs automatically as you type.
- 3If invalid, the exact error position and reason are shown.
Tips
- Mixing tabs and spaces for indentation is one of the most common YAML errors and one of the hardest to spot visually — if the reported line looks fine, check its indentation character by character.
Frequently asked questions
What people use it for
Debug a CI pipeline that won't parsePaste your GitHub Actions/GitLab CI YAML to find the exact indentation or syntax break.
Check a Kubernetes manifest before applying itCatch a YAML syntax error before `kubectl apply` does.
Verify config pasted from docs or a chatPasted YAML often loses indentation — this points straight at the break.
Related guides
- How to read JSON with a tree viewerA tree viewer turns a wall of brackets into a structure you can expand, search and copy paths from. Here's how to use one effectively.
- JSON parse errors explained: 'Unexpected token', 'Expected comma or brace', and the restWhat each common JSON error message actually means, the usual cause, and how to find the spot fast using line and column.
- How to format JSON (and actually understand the errors)JSON looks like a JavaScript object but follows stricter rules. Here's what those rules are and how to read the errors when they're broken.
Related tools
All developer toolsYAML to JSONConvert YAML to JSON — including anchors, merge keys and multi-document files.JSON to YAMLConvert JSON to YAML format.JSON ValidatorValidate JSON syntax and pinpoint errors instantly.JSON Viewer & FormatterView, format, validate, edit and beautify JSON with an interactive tree view, plus a shareable link.
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YAML Validator