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Free Developer Tool

JSON Unflattener

Convert flattened JSON back into nested objects and arrays.

What is JSON Unflattener?

The JSON Unflattener reconstructs nested JSON structures from flattened key-value pairs, making data easier to use in applications.

How to use

  1. Paste flattened JSON.
  2. Generate the nested structure.
  3. Copy the result.

Features

  • Restore nested objects
  • Support arrays
  • Fast conversion
  • Valid JSON output

Common Use Cases

  • Rebuilding exported data
  • Preparing API payloads
  • Restoring configuration files
  • Working with flattened datasets

Example

Input
{
  "user.name":"John"
}
Output
{
  "user":{
    "name":"John"
  }
}

FAQ

Can flattened JSON always be restored?

Yes, provided the flattened structure follows a supported key format.

Does it support arrays?

Yes. Array paths are reconstructed whenever possible.

Is the output valid JSON?

Yes. The generated result is valid nested JSON.