OnlineCodeEditor

YAML editor and validator

The example uses an anchor and a merge key. Press Run to see the resolved data as JSON.

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See what your YAML really means

YAML is parsed with the yaml library (YAML 1.2). Run shows the parsed result as JSON, so you can check that an anchor merged the way you intended or that a value like no or 08 has the type you expect. Alias expansion is capped to protect against “billion laughs” documents.

Editing help

Indentation errors and duplicate keys are underlined with their position. Prettier formatting normalises spacing and lists. The outline lists top-level keys for quick navigation in long CI or Kubernetes files.

How to use it

  1. Press Run to see the JSON view.
  2. Break the indentation of a key to see the error.
  3. Format with Shift+Alt+F.

Questions

Which YAML version is used?

YAML 1.2 (core schema), as implemented by the yaml npm library.

Are multiple documents supported?

Yes. Documents separated by --- are parsed separately and shown as an array.

Can it validate Kubernetes or GitHub Actions schemas?

Not yet. Only YAML syntax is validated.