Settings
Result appears here after you select
{ } How to use
- Paste your nested JSON.
- Change the key delimiter if you want something other than a dot.
- Select Process to get one key per leaf value.
{ } How it works
JSON Flatten works on the text you provide. Adjust the options, then select Process ▸ and it runs entirely in your browser — nothing is uploaded to a server — then shows the result in the Output panel.
Inputs
- JSON input — paste or type your input in the left panel (use Sample for an example)
- Key delimiter — a value (default: ".")
Output
JSON — copy it, download it, or switch the Output panel to Tree view to explore it.
{ } Common uses
- Prepare nested data for CSV or a spreadsheet, one column per leaf value.
- Compare two documents key by key without walking the nesting by hand.
- Build a path-to-value lookup — the shape translation files and flat configs use.
{ } Limitations
- Array items become numeric path segments, so items.0.name is a key and the result is a flat object rather than a list.
- A key that already contains the delimiter becomes ambiguous once flattened. Choose a delimiter your keys never use.
{ } FAQ
Is my data uploaded to a server?
No. Everything runs locally in your browser — your files never leave your device.
Can I process more than one file at once?
This tool works on one input at a time.
Is this tool free?
Yes — it’s completely free and needs no sign-up.
Can I get the nested structure back?
JSON Unflatten rebuilds it from the same delimiter. Numeric segments come back as object keys rather than as arrays.
Which delimiter should I use?
A dot suits most data. If your keys contain dots, pick something they never contain — a slash or a double underscore, for example.