JSON Path Extractor / Flatten

Deeply nested JSON is hard to compare or iterate over programmatically. Flatten unrolls such a structure into a flat list of "path: value" pairs (e.g. store.book[0].price: 12.99), and Unflatten rebuilds it.

How to use it

• Flatten: paste nested JSON and get a flat list of every leaf value with its full path.
• Unflatten: paste a list of "path: value" pairs to rebuild a nested JSON structure from it.
• The path notation matches this site's JSONPath and JSON Diff tools — items[0].name for array elements.

Common uses

• Turning a deeply nested API response into a flat list for import into a spreadsheet or analytics system.
• Building a translation dictionary or config back into nested JSON from flat keys (form.errors.email).
• Quickly finding every value on a given topic in a very large JSON document via a flat path list.

Things to keep in mind

Array index notation varies between libraries — this tool uses items[0], though some write items.0 without brackets.

Unflatten requires that paths don't conflict with each other (e.g. one and one.two at the same time) — otherwise the structure can't be unambiguously rebuilt.