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ToolSuite
JSON, XML & YAML Tools

JSON Unflattener

Rebuild nested JSON from flat dotted paths.

Processed in your browser

Your result will appear here as soon as you add some input.

How to use it

  1. 1Paste your document into the input box, or type it directly.
  2. 2Adjust the options if you need something other than the defaults.
  3. 3The result updates as you type.
  4. 4Copy the result to your clipboard or download it as a file.

About the JSON Unflattener

Numeric path segments and bracketed indexes both rebuild arrays, so `items[0].id` and `items.0.id` produce the same structure.

Keys named `__proto__`, `constructor` or `prototype` are dropped rather than written. Rebuilding an object from attacker-supplied paths is the classic prototype pollution vector, and this is where it would happen.

Questions people ask

Is your document uploaded to a server?

No. This tool runs entirely in your browser using standard web APIs, so your document never leaves your device. You can confirm it by opening your browser's network panel while the tool runs, or by disconnecting from the internet after the page has loaded.

Is it free, and do I need an account?

Yes, it is free, and there is no account, no sign-up and no watermark on the result. The project is funded by optional donations.