JSON Flattener / Unflattener
Flatten nested JSON to dot notation — and reverse it
Runs 100% in your browser — nothing is ever uploaded.
What is JSON Flattener?
Flatten deeply nested JSON into a single-level object with dot-notation paths (user.address.city) — or reverse the process to rebuild the nested structure, including arrays. Pick dot, slash or underscore separators to match your config system or analytics pipeline.
How to use JSON Flattener
- Paste your nested JSON into the input box or click “Load sample” to try it.
- Adjust the options in the toolbar if needed (delimiter, table name, format …).
- Click the convert button — the flat JSON appears instantly in the output pane.
- Copy the result with one click or download it as a file.
ConvertLab FAQ
Is the JSON flattener free?
Yes — 100% free, no signup, no limits, no watermarks. Use it as often as you like.
Does unflatten restore arrays?
Yes — objects whose keys are consecutive integers (0, 1, 2 …) are automatically converted back into real JSON arrays during unflattening.
Is my data uploaded to a server?
No. The conversion runs entirely in your browser with JavaScript — your data never leaves your device, which makes the tool safe even for confidential files.
Are these converters free?
Yes — every ConvertLab tool is 100% free with no signup, no limits and no ad walls.
Is my data uploaded anywhere?
No. All conversions (JSON, CSV, XML, YAML, INI, .env) run entirely in your browser. Nothing ever leaves your device.
Do these tools work offline?
Yes — once the page is loaded, every converter works without an internet connection.