JSON Flattener Tool

Flatten nested API responses and analytics payloads into reliable key-value output or CSV-ready extracted rows with path controls, source mapping, and field profiling.

JSON Flattener Tool

Flatten nested JSON into export-ready key-value output with array controls, path filtering, source mapping, and large-file-safe processing.

Shortcuts: Ctrl/Cmd+Enter run, Ctrl/Cmd+Shift+C copy output, Ctrl/Cmd+M maximize output panel.

360 B22 linesDepth 7Valid JSON
Nested API payload with arrays of objects and metadata.

Need Reverse Reconstruction Only?

The dedicated JSON Unflatten Tool is focused on rebuilding nested JSON from flat keys, JSON Lines batch rows, and conflict-heavy ETL exports.

How to Use

  1. Paste or upload nested JSON in the input panel.
  2. Choose path notation, array handling, and any scope or ignore filters you need.
  3. Enable row extraction when you want record-path based rows and optional metadata columns for CSV-style workflows.
  4. Review flattened JSON, row extraction output, field profiles, or key-value lines while searching the generated keys.
  5. Use the path preview and field dictionary to connect flat columns back to their original nested source paths before exporting.

Related Tools

JSON Unflatten ToolJSON Key ExtractorJSON Path FinderJSON to Table

Frequently Asked Questions

How does the JSON Flattener handle arrays?

You can flatten arrays with indexes, preserve them, stringify them, join primitive values, use only the first item, or explode the selected array into flat rows.

Can I extract rows for CSV or analytics workflows?

Yes. Enable row extraction, choose a record path that resolves to an array, and optionally carry parent metadata fields into every extracted row.

Can I flatten only one part of a larger JSON document?

Yes. Use the selected path control or path prefix filters to flatten only the subtree you care about instead of the entire document.

Can I ignore specific keys or paths while flattening?

Yes. You can ignore exact key names, include only selected path prefixes, or exclude path prefixes so the output stays focused and export-ready.

Will large JSON files freeze my browser?

Large JSON inputs automatically run in a Web Worker with progress updates and a cancel option to keep the UI responsive.

Is my data uploaded to DevToolsBuilder servers?

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