Does the viewer upload JSON?
No. The tree is built in the browser.
jfmt.dev
JSON Viewer
Paste JSON to explore it as a tree. Expand and collapse nodes locally — the document never leaves this device.
JSON formatter
Input
Output · preview.json
{ }
Run a tool to see a polished result here
Tree view vs pretty print
Pretty print is still text. The viewer turns objects and arrays into foldable nodes so large payloads are easier to scan. Switch to the homepage formatter when you need to copy indented JSON.
Sample input on this page
The editor is prefilled with a small example for JSON Viewer. The viewer renders a collapsible tree so you can inspect nested objects and arrays without flattening the file. Replace it with your own file; the sample and your payload stay in this tab.
{
"service": "jfmt",
"enabled": true,
"nested": { "retries": 3, "tags": ["json", "local"] }
}How to use this tool
- Paste JSON into the JSON Viewer editor. The file stays in this browser tab and is not uploaded to jfmt.dev.
- Click Run. The viewer renders a collapsible tree so you can inspect nested objects and arrays without flattening the file.
- Copy the output, or continue with a related tool below. Related tools on this site include beautify, validate, minify, JSON to CSV, JSON to YAML and JSON to XML — all local.
- JFmt runs in a Web Worker in this tab. Do not paste production secrets if you share your screen.
When this page is the right choice
This dedicated JSON Viewer URL matches that search intent; the homepage stays the general formatter. The viewer renders a collapsible tree so you can inspect nested objects and arrays without flattening the file. Related tools on this site include beautify, validate, minify, JSON to CSV, JSON to YAML and JSON to XML — all local. JFmt runs in a Web Worker in this tab. Do not paste production secrets if you share your screen. Read errors in the output pane instead of sending production payloads to another service.
Related tools
FAQ
Can I edit in the tree?
Use the left editor to change text, then run the viewer again. The tree is for inspection.
What if JSON is invalid?
The viewer needs valid JSON. Validate or Repair first.
Does this tool upload my file?
No. Parsing and conversion run in a Web Worker in this tab. jfmt.dev does not receive the payload.
Why is there a separate URL from the homepage?
So people searching for this operation land on a page that already selects it. The viewer renders a collapsible tree so you can inspect nested objects and arrays without flattening the file.