Rebuild nested JSON
Paste a flat object whose keys are dotted paths and rebuild the original nested JSON. Turn on array rebuilding so numeric path segments become arrays — the exact inverse of Flatten JSON. The result is saved privately in your account.
No sign-up needed — runs instantly in your browser.
How it works
- 1Paste your flat JSON object
- 2Set the separator and options, then press Run
- 3Download the nested JSON or find it in your files
Frequently asked questions
- When do I get arrays vs objects?
- With "Rebuild arrays" on, integer path segments (0, 1, 2…) create arrays; off, every level stays an object with string keys.
- Does it reverse Flatten JSON exactly?
- Yes — use the same separator and keep array rebuilding on to reproduce the original structure.
Related tools
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Developer