Convert JSON and YAML
Convert JSON documents to readable YAML, or YAML documents to formatted JSON, in your browser. Useful for config files you would rather not paste online.
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JSON and YAML converter in three steps
FileGizmo converts JSON to readable YAML and YAML back to formatted JSON without uploading configuration, application data, or secrets. Choose a .json, .yaml, or .yml file, select the direction, and set the output indentation. A dedicated browser worker validates the source, creates a preview, and returns a correctly named UTF-8 download.
JSON and YAML overlap but are not identical. YAML comments, anchors, tags, and presentation choices cannot all survive a round trip through JSON. This tool reads every document in the file, resolves merge keys, applies an alias-count safety limit, and uses the standard JSON-compatible value model. YAML timestamps and special scalar types may be normalized when represented in JSON. JSON output is strict and formatted; YAML output favors readable block style and avoids unnecessary aliases for repeated objects. Parse errors are reported before a download is created, including useful line context when the parser supplies it. Files stay on the device, and the YAML dependency is isolated to the data worker. Review configuration diffs before deployment, especially when an application depends on custom YAML tags or comment-based documentation.
Large JSON integers are kept exact and written as unquoted YAML numbers. When converting YAML back to JSON, an integer beyond JavaScript’s safe range is written as a quoted decimal string instead of a rounded number.
- 1
Choose a JSON or YAML file and output direction
- 2
Select indentation and document options
- 3
Convert preview and download
Frequently asked questions
Are YAML aliases supported?
Yes. Aliases and merge keys are resolved, with a limit of 100 aliases so a file built to expand without end stops early.
Will comments survive conversion?
No. JSON has no comment model, so comments are not preserved across both directions.
Can it convert multiple YAML documents?
Yes. A file with several documents, each starting with a line of three dashes, becomes one JSON array with the documents in file order, and the result line says how many there were.
Is configuration data uploaded?
No. Parsing and serialization occur in a dedicated browser worker.