Developer Tools
Expand flat path-based JSON into nested objects and arrays.
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.
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.
Use json unflatten when you need a fast browser-based result without extra setup. It works well for quick checks, one-off tasks, and routine formatting or calculation work.
Read step-by-step usage guidance, best practices, and common mistakes.
See common questions and answers about input, output, and tool usage.
Review practical input and output examples before running the tool.
Find similar and supporting tools for adjacent actions and follow-up tasks.
Input
{"user.id":7,"user.name":"Anna"} Output
{
"user": {
"id": 7,
"name": "Anna"
}
} Useful when flat dot-notation keys need to become a normal nested object again.
Input
{"orders[0].id":101,"orders[1].id":102} Output
{
"orders": [
{
"id": 101
},
{
"id": 102
}
]
} Useful when flattened array paths need to be restored into array items.
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.
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.