JSON unflattener
Rebuild nested JSON from typed JSON Pointer records. Detect conflicting paths, missing parents and incomplete arrays.
Up to 1,000,000 input characters, 50,000 values per JSON document and 64 nesting levels. Duplicate keys, negative zero and numbers that cannot safely retain their decimal value are rejected. Quote precision-sensitive numbers as strings. Formatting and object member order may change. Processing stays on your device. Each JSON Pointer is limited to 20,000 characters. Paste text to process locally. Review the result before downloading. Results update as you type. Up to 1,000,000 characters.
Your result
How to use JSON unflattener
- Paste a complete path document from JSON flattener.
- Review any path or type conflicts and correct the input.
- Download the reconstructed JSON and report.
Useful next steps
Use the reversible path document
Paste the complete happytails-json-paths-v1 document created by JSON flattener. It includes a format field and records with path, type and, for scalar records, value. Other flat JSON conventions, including arbitrary dotted keys, are not accepted.
Keep arrays and objects distinct
Explicit container records preserve empty containers and numeric object keys. Records may arrive in any order. Every child must have a matching object or array parent; array indices start at zero and must be contiguous without leading zeros.
Resolve conflicts before exporting
Duplicate paths, missing parents, children under scalar values and type mismatches block reconstruction. The tool returns a fixed error report rather than a partial document. Once the paths are consistent, download the reconstructed JSON.