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YAML Validator

Check YAML indentation, keys, anchors and quotes, with the line and column of every problem.

Your YAML

Status: —

Top level keys

—

Problems

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Tabs, inconsistent indentation, duplicate keys, broken anchors and unclosed quotes are all reported locally.

How to use the YAML Validator

  1. Paste the YAML document you want to check.
  2. Click Validate to scan indentation, keys, anchors and quotes.
  3. Read the top level key summary and the line and column of each problem.

Features

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Frequently Asked Questions

Common questions about the free online yaml validator.

It scans the document line by line for tabs, uneven indentation, duplicate keys, broken anchors, unknown aliases and unclosed quotes.
The YAML specification forbids tab characters in indentation, so a tab that looks correct in an editor can make a document invalid.
Keys are tracked per indentation block, so the same name twice at the same level is reported while repeats in sibling blocks are allowed.
Yes. Every problem is listed with its line number and column number so you can jump straight to the character.
No. This tool checks the syntax and structure of the YAML itself, not whether the data matches an external schema.
Each top level key is listed with the type of value found, such as map, sequence, string, number, boolean or empty.
No. The whole check runs in your browser, so your document never leaves your device.
Yes, the YAML validator is completely free with no account and no usage limits.

Last updated: October 10, 2026