JSON Unflatten
The inverse of JSON Flatten. Paste a flat JSON object whose keys use dot-notation (`a.b.0`) or array brackets (`a.b[0]`) and rebuild the nested structure. Numeric segments are treated as array indices, everything else as object keys. Useful for parsing form-data style payloads, CSV → nested JSON, or undoing a flatten operation. Runs entirely in your browser — free, online, no upload.
Privacy
Runs entirely in your browser — nothing is sent to any server.
Cost
Free. No sign-up, no watermark.
Type
Transformer
Related tools
Tools that work with the same formats — most users open one of these next.
QR Code Reader
Scan a QR code from any image and decode it to text — free, online, runs entirely in your browser.
QR Code Generator
Generate a QR code from any text, URL or contact data — pick error correction and scale, get a PNG.
File to Hex Dump
Convert any file's bytes to a hex dump (with ASCII sidecar), plain hex, C array or comma-separated bytes.
Hex to Binary File
Parse a hex dump or hex string back into a binary file — strips offsets, ASCII columns, prefixes and separators automatically.
Wi-Fi QR Code Generator
Generate a Wi-Fi QR code as a PNG — scanning it auto-joins the network. Supports WPA / WEP / open networks and hidden SSIDs.
vCard QR Code Generator
Generate a QR code that contains a digital business card (vCard) — scanning it lets the phone save the contact in one tap.
Frequently asked
Is JSON Unflatten free to use?
Yes. JSON Unflatten is completely free with no sign-up, no watermark, and no usage limits. Toolsly does not charge for any of its tools.
Do my files and data stay private?
Yes — JSON Unflatten runs entirely in your browser using your device's CPU. Files and text are never uploaded to our servers, so your data stays private.
How does JSON Unflatten work?
Open JSON Unflatten, paste or fill in the input fields, and the result updates instantly. Everything runs in your browser — no upload, no waiting.
Which browsers does JSON Unflatten support?
Any modern browser works — Chrome, Firefox, Safari, and Edge on desktop and mobile. JSON Unflatten uses standard web APIs and does not require any plugin, extension, or sign-up.