YAML Reserved Character Error – Quote @ and Backtick Values

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YAML reserves @ and the backtick at the beginning of plain scalars. Quote values such as @home instead of leaving them bare.

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YAML plain scalar troubleshooting

How to fix a reserved character at the start of a YAML value

The validator starts with @deploy as an unquoted value. YAML does not allow a plain scalar to begin with @ or a backtick, so quote the complete value when those characters are data rather than syntax. This tool is free to use. No account or payment is required.

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What you can do here

  • YAML 1.2 parser validation
  • Duplicate mapping key detection
  • Preloaded broken YAML example
  • Readable parser feedback
  • .yaml and .yml file import
  • Browser-local processing

Steps

  1. Find the scalar that begins with @ or a backtick.
  2. Confirm the character is intended data rather than a typo or templating placeholder.
  3. Quote the full scalar and validate the document again.

Plain YAML scalars have lexical restrictions

YAML permits many unquoted strings, but not every character sequence can begin a plain scalar. Reserved leading characters are one reason a value that looks harmless in another configuration format may require quotes in YAML.

Quoting is safer than deleting meaningful characters

If @ or a backtick is part of an account name, token placeholder, command fragment, or other intended string, removing it changes the data. Quoting preserves the value while making the YAML syntax unambiguous.

Reserved YAML scalar start example

The @ character is preserved by quoting the complete string.

Invalid YAML

handle: @deploy

Corrected YAML

handle: "@deploy"

Common questions

Frequently asked questions

Why is @ invalid at the start of an unquoted YAML value?

YAML reserves @ at the start of plain scalars, so a value beginning with it needs a quoted or other explicit scalar style.

Are backticks string quotes in YAML?

No. Backticks are not YAML string delimiters, and a plain scalar cannot start with a backtick. Use single or double quotes instead.

Will quoting change the string value?

Normal YAML quoting marks the scalar boundary; the parsed string can still contain the leading reserved character as data.

Recommended next steps

Invalid Escape Sequence in YAMLFix unsupported backslash escapes inside YAML double-quoted strings.Unclosed Quoted String in YAMLFind a single- or double-quoted YAML scalar that reaches the end without a closing quote.YAML Validator Online – Check YAML SyntaxPaste any YAML document and inspect parser feedback locally.

Debugging a specific YAML issue? Browse YAML troubleshooting.