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Find clear answers to common questions about JSON Unflatten, including usage, output, and common issues.
Use this JSON Unflatten tool to convert flat path-based JSON into a nested JSON structure again. It is useful when you receive flattened exports, mapping results, analytics-style path objects, or intermediate transformed data and want to rebuild the original nested shape. The tool supports dot notation for objects and bracket indexes for arrays.
JSON Unflatten is built for development, debugging, formatting, and quick technical checks directly in the browser.
It converts a flat object with path-based keys into a nested JSON structure.
Yes. Keys like items[0].name are restored into arrays with indexed objects.
Use a JSON object where each key is a path such as user.name or orders[0].id.
Flatten turns nested JSON into path-based keys, while Unflatten does the reverse.
The most common reasons are conflicting paths, invalid JSON, or inconsistent key notation.
JSON Unflatten is built for development, debugging, formatting, and quick technical checks directly in the browser.
Start by checking the input format, removing accidental spaces or unsupported characters, and comparing your input against the example pattern on the page.
Fix: Use a JSON object with string keys like user.id or items[0].name.
Fix: Use dot notation for objects and bracket indexes for arrays.
Fix: Validate or format the input first before unflattening.
Fix: Avoid mixing paths that force the same field to be both a primitive value and a nested object.
Fix: This tool rebuilds structure, but exact ordering may differ.
If you want to see realistic input and output patterns, open the examples page. If you want step-by-step usage guidance, open the guide page.
Open the main JSON Unflatten page to test your own input and generate a live result.