Does key order matter?
No. Objects are compared by key, not by the order keys appear in the file.
jfmt.dev
JSON Diff
Paste left and right JSON to list every added, removed, and changed path. Built for API payloads, config reviews, and snapshot tests.
JSON formatter
Input
Output · preview.json
{ }
Run a tool to see a polished result here
How the diff works
Both sides are parsed, then compared as trees. You get a path-level report, not a line-by-line text diff — so key order and whitespace do not fake a change. Processing stays local.
Sample input on this page
The editor is prefilled with a small example for JSON Diff. Diff compares two JSON documents and lists structural changes by path, so you can review config or API payload drift. Replace it with your own file; the sample and your payload stay in this tab.
{
"name": "jfmt",
"version": 1,
"flags": { "dark": true }
}How to use this tool
- Paste JSON into the JSON Diff editor. The file stays in this browser tab and is not uploaded to jfmt.dev.
- Click Run. Diff compares two JSON documents and lists structural changes by path, so you can review config or API payload drift.
- 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 Diff URL matches that search intent; the homepage stays the general formatter. Diff compares two JSON documents and lists structural changes by path, so you can review config or API payload drift. 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 diff huge files?
The editor is meant for typical API and config sizes. Extremely large trees may feel slow in the browser.
Is either side uploaded?
No. Both documents stay in memory on this device.
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. Diff compares two JSON documents and lists structural changes by path, so you can review config or API payload drift.