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YAML Formatter

Paste YAML and get it validated, indented, and pretty-printed. Catch common mistakes like tab characters and bad anchors.

Updated April 2026

Expected "key: value" at: "# project config"

What it does

Paste YAML and get it validated, indented, and pretty-printed. Catches common mistakes — accidental tabs, mis-indented lists, trailing colons — with line-specific error messages. All parsing happens in your browser, so config files with secrets never leave the page.

Convert to JSON with YAML JSON converter, compare with JSON diff checker, or inspect a full JSON payload using JSON formatter.

How to use it

  1. Paste YAML into the input box.
  2. Click Format — invalid YAML shows a line-anchored error.
  3. Pick 2 or 4-space indent.
  4. Copy the formatted output.