Data & Tables
JSON Unflattener
Unflatten JSON online. Convert path-based keys back into nested objects locally in your browser without uploading data.
Tool
Unflatten JSON online. Convert path-based keys back into nested objects locally in your browser without uploading data.
This tool runs in your browser. Your input is processed locally and is not uploaded.
About this Tool
Use this JSON Unflattener to rebuild nested objects from flattened keys such as customer.name or address.city. The tool can choose path notation, detect collisions, create nested objects, and optionally rebuild array-like paths when they are unambiguous. It complements the JSON Flattener and is most reliable when the flattened data uses a consistent naming convention.
Examples
- { "order.id": "A-1001", "customer.name": "Ada", "customer.country": "DE", "total.amount": 39.9 }
Frequently Asked Questions
Is my JSON data uploaded to a server?
No. The tool parses, transforms, previews, and exports data locally in your browser without uploading your input.
When can flattened JSON be unflattened safely?
It is safest when keys use consistent path notation and do not contain ambiguous separators that could also be literal key characters.
What is a path collision?
A collision happens when one key needs to be both a value and an object path, such as "user" and "user.name" in the same object.
Can arrays be rebuilt?
Array-like paths can be rebuilt when indexes are clear and consistent. Irregular arrays should be reviewed carefully.
What file sizes are practical in the browser?
Small and medium tables are the best fit. Very large files can use a lot of memory because parsing, previews, and exported results all live inside the browser tab.