Rebuild a nested JSON object from a flat map of dot notation keys, which is the exact inverse of flattening and just as useful. Config systems, translation files and form data often arrive as a single level of dotted paths, and this tool expands them back into the real nested structure your code expects. It parses each key, splitting on dots and reading bracketed numbers as array indices, then creates the intermediate objects and arrays needed to place every value. Leaf values keep their original JSON type, so numbers and booleans are not turned into strings. Paste a flat JSON object whose keys are dotted paths, click unflatten, and copy the nested result. Everything runs locally in your browser, so the data you rebuild never leaves your device or gets logged elsewhere.
Rebuild a nested JSON object from a flat map of dot notation keys, which is the exact inverse of flattening and just as useful. Config systems, translation files and form data often arrive as a single level of dotted paths, and this tool expands them back into the real nested structure your code expects.
Yes. JSON Unflatten is completely free, with no sign-up and no usage limits.
Yes. JSON Unflatten runs in any modern web browser. There is nothing to download or install.
Yes. JSON Unflatten runs entirely on your device in your browser, so nothing you enter is uploaded to a server.