JSON Unflattener — Free Online Tool

Expand flat dot-notation JSON back to nested structure. JSON Unflattener is a free online tool from the ToolsRift JSON Tools collection. It runs entirely in your browser — nothing to install, no signup, and your data never leaves your device.

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How to use JSON Unflattener

Paste a flat object with dot-notation keys and it is rebuilt into the nested JSON structure those paths describe.

Frequently asked questions

What input does it expect?

A flat object whose keys are paths like user.address.city; these are expanded into nested objects.

How are array indexes handled?

Numeric path segments such as items.0 are rebuilt as array elements in the correct positions.

Is this the opposite of flattening?

Yes — unflattening reverses the JSON Flattener, turning dot-notation keys back into nested structure.

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