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JSON Flattener

Flatten nested JSON into key paths and rebuild the original structure.

The JSON Flattener converts nested objects and arrays into flat key-value pairs using dot or underscore separators. It can also rebuild nested JSON from flattened keys, including bracket-style array paths.
Mode

How to use

  1. Choose Flatten or Unflatten mode.
  2. Select the separator and array style.
  3. Paste JSON and read the converted result.

Frequently asked questions

How are arrays represented when flattened?

Bracket style uses names like items[0]; dot style uses names like items.0.

Can flattened data be restored?

Yes, Unflatten mode rebuilds objects and arrays from the paths.

What happens on path collisions?

Flattening stops with an error when two keys would produce the same path.

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