JSON Flattener converts nested objects into flat key paths that are easier to scan, compare, export, or map into spreadsheets. It is useful for APIs, logs, and configuration files.
Yes. The tool is free and runs directly in your browser with no account required.
No. Processing happens locally in the browser tab. Your JSON is never sent to a server.
Array items become keys with their numeric index appended, e.g. user.tags.0 and user.tags.1 for the first and second items in a tags array.
Yes — the default separator is a dot (.), but you can set it to any short string (e.g. an underscore or a colon) using the Separator field.
Yes — switch to Unflatten mode and paste dot-notation flat JSON to reconstruct the original nested object structure.
Spreadsheets work best with flat columns. Flattening nested JSON into dot-path keys turns each unique path into a column header, making the data easy to import into a CSV or spreadsheet tool.
They're preserved as-is at their flattened key — flattening only restructures the key paths, it doesn't change the underlying values' types.
There's no hard-coded depth limit, but extremely deep or large JSON documents may take longer to process depending on your browser and device.
