Compare JSON files online
Paste or upload two JSON documents and the diff appears automatically: added keys, removed keys and changed values, through every level of nesting. Format and copy either side in one click. Your JSON stays in your browser.
- 100% free forever
- Private, in your browser
- Instant results
How do I compare two JSON files?
Paste or upload each document and the diff appears automatically, no button to press. DataSort walks both key by key and item by item and shows a tree where added keys, removed keys and changed values are colour coded, with the old value beside the new. Format tidies messy JSON and Copy puts a side on your clipboard. It runs in your browser and is free with an account at five comparisons every twenty minutes.
- 1Paste JSON A, or use Upload to load a .json file.
- 2Paste or upload JSON B. The diff appears on its own.
- 3Use Format on either side to pretty print messy JSON before you read it.
- 4Read the colour coded tree: green is added, red is removed, amber is changed.
- 5Export the differences as JSON, or Copy either side to your clipboard.
Everything the JSON diff shows you
Added and removed keys
Keys that appear in only one document are colour coded green (added) or red (removed) at the exact level they sit in the tree.
Changed values
A value that differs shows the old value struck through beside the new one, so you see precisely what moved.
Nested objects, every level
Objects are compared key by key all the way down, so a change three levels deep is shown in place, not just at the top.
Arrays by position
Array items are compared by index, so an appended, removed or edited element is highlighted where it belongs.
Format and copy
Tidy messy JSON with one click, and copy either side to your clipboard, without leaving the page.
Private and free
Your JSON is read in the browser and never uploaded. Free with an account at five comparisons every twenty minutes, unlimited on any paid plan.
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Common questions about comparing JSON
How do I compare two JSON files?
Does it work with nested objects and arrays?
Is my JSON uploaded anywhere?
Is comparing JSON free?
How It Works: Technical Methodology
Deterministic, local diff
The diff is computed in your browser, not by an AI model. Both documents are walked key by key and item by item, so the result is exact and repeatable.
Privacy & processing
A stateless architecture: your JSON is parsed locally and never stored on our servers. The only server call counts your free comparisons so the limit is fair.