JSON Unflattener

Convert flat dot-notation JSON keys back into a nested object structure.

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Frequently Asked Questions

What is JSON unflattening?
Unflattening is the reverse of flattening. It takes a flat object with dot-separated keys like {"a.b.c":1} and reconstructs the nested structure: {"a":{"b":{"c":1}}}.
What separator should I use?
Use the same separator that was used when the JSON was flattened. The default is a dot. If your keys use underscores or slashes as separators, select the matching option.
What happens if a key segment already exists as a non-object value?
If a conflict is detected during reconstruction, the later key path overwrites the earlier value. For best results, ensure all key paths are consistent and non-conflicting.
Can I unflatten JSON that was not created by this tool?
Yes, as long as the input is a valid flat JSON object using a consistent separator character for all keys. The tool is not limited to output from the JSON Flattener.

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