JSON Unflatten Tool

Reconstruct nested JSON from flat ETL rows, CSV-style records, dotted keys, bracket notation, or JSON Pointer paths with conflict visibility and reversibility checks.

JSON Unflatten Tool

Convert flat dotted, bracketed, slash, or pointer-style keys back into nested JSON with conflict diagnostics and reversibility checks.

Focused reverse-structure workflow for CSV-style flat rows, ETL exports, and flatten to unflatten debugging.

Sample Templates

Start with realistic flat-key shapes to see objects, arrays, conflicts, and verification behavior.

Real-world CSV/ETL output often mixes dotted keys with explicit array indices.

Paste, upload, or drag a flat JSON file here. JSONL batch rows are supported too.

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How to Use

  1. Paste or upload flat JSON or JSON Lines rows in the left panel.
  2. Choose mixed-auto parsing or force a specific notation such as dot, bracket, or JSON Pointer.
  3. Adjust numeric segment, conflict, and max-depth behavior to match your source data.
  4. Review nested JSON, path preview diagnostics, and re-flatten verification before exporting.

Related Tools

JSON FlattenerJSON Key ExtractorJSON Path FinderJSON to Table

Frequently Asked Questions

Can the unflatten tool handle mixed dotted and bracketed paths?

Yes. The default mixed-auto parser understands slash, bracket, JSON Pointer, and dotted segments in the same input when the path shape is unambiguous.

How does array detection work?

Numeric path segments can auto-create arrays, always remain object keys, or always become arrays depending on the numeric segment mode you choose.

What happens when flat keys conflict?

You can fail fast, overwrite, skip later values, or merge compatible containers. The audit panel records exactly what happened for each conflict.

Is my flattened JSON uploaded anywhere?

No. All processing happens locally in your browser. No data is uploaded or stored.