JSON Toolkit

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YAML to JSON Converter

Paste YAML or open a .yaml file to convert it to JSON. Anchors, aliases and <<: merge keys are expanded, files with several --- documents become an array, and errors show the exact line and column.

JSON ⇄ YAML Converter

Turn YAML into JSON. Comments are dropped, anchors and << merge keys are expanded, and files with several --- documents become an array.

How to use the YAML to JSON Converter

  1. Paste your YAML, or click Open file… to load a .yaml or .yml file.
  2. Click Convert to JSON.
  3. Copy or download the JSON, or open it in the formatter to explore it as a tree.

Features

  • Merge keys (<<: *defaults), as used in Docker Compose and CI files
  • Files with several --- documents become a JSON array
  • Exact line and column for syntax errors and duplicate keys
  • Warnings for values JSON cannot represent, such as .nan or very large integers
  • Protection against “alias bomb” files that would expand to a huge size

Frequently asked questions

Are YAML comments kept?
No. JSON has no comments, so they are dropped during conversion.
Does on: become true?
No. The converter follows YAML 1.2, where on, yes and no are plain text, so a GitHub Actions on: key stays the text "on".
Is it safe to paste YAML I don't trust?
Yes. YAML is only read as data, no code or custom tags are executed, and files that try to expand into huge amounts of data are refused.

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