DataToolsLab
YAML Tools

YAML Type Coercion Checker

Find values that coerce to different types in YAML 1.1 vs 1.2.

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What is Coercion Check?

A safety scanner for the YAML 'Norway problem': tokens like yes, no, on, off, and leading-zero numbers parse differently under YAML 1.1 vs 1.2 schemas.

How it works

Each candidate token is probed with js-yaml under both CORE (1.2) and YAML 1.1 schemas; differing results are flagged with a fix suggestion.

  1. Enter your input. Type or paste your input into the field above — the tool responds instantly.
  2. Review the result. Output updates live as you type. Everything runs entirely in your browser.
  3. Copy or download. Use the Copy button to grab the result, or Download to save it as a file.

Examples

Realistic sample

Paste or type any realistic input — the tool computes the result locally and instantly.

Common mistakes

Expecting a server round-trip

Nothing is uploaded — every tool in this category runs entirely in your browser.

Frequently asked questions

Why does quoting fix it?

Quoted scalars are always strings in every schema — wrapping the token in quotes makes its type unambiguous regardless of parser version.

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