JSON Diff & Comparator — Compare JSON Documents Side by Side
Paste two JSON documents into the left and right panes and the diff engine walks both trees key-by-key and index-by-index, emitting a color-coded report of additions, deletions, and value changes. Comparison is semantic, so reordering keys inside an object does not register as a change — only real structural and value differences surface.
This is the tool for reviewing what actually changed between two API responses across environments, spotting drift between a committed fixture and a fresh capture, validating migrations where key ordering varies, or debugging regressions where a field silently flipped type. It is also useful for config review: diff a production config against staging and see every real delta in seconds.
Added values are highlighted in green, removed in red, and changed values show both old and new. A summary header reports the total number of added, removed, and changed paths so you can gauge impact at a glance. A swap button flips the two inputs without reloading, and identical documents render an explicit "no differences" banner so you do not have to scan blank output.
Both documents stay in the browser — the diff runs locally in JavaScript with no upload, no logging, and no remote call.
About JSON Diff
Compare two JSON documents semantically — key order doesn't matter. See exactly what was added, removed, or changed with color-coded highlighting and a summary of total changes.
- Semantic comparison (key order independent)
- Color-coded additions and deletions
- Change summary with line counts
- Swap sides with one click
- Identifies identical documents
100% client-side. Your inputs never leave your browser. Ads via AdSense (consent required).
Frequently asked questions
How do I compare two JSON documents?
Paste JSON A on the left and JSON B on the right. The diff tool parses both, aligns matching keys, and highlights changes side by side: green for additions, red for removals, and yellow for value changes. It handles nested objects and arrays structurally — so adding an item in the middle doesn't mark everything after as changed, unlike text diffs. You can collapse equal sections to focus only on what's different.
Is the JSON diff tool free?
Yes, fully free with no signup and no size limit beyond browser capacity. You can run as many comparisons as you want, which is why people use it for API response regression testing, config audits and schema change review. JSONCraft has no premium tier — every tool is open at full capability.
Does the diff upload my JSON documents?
No. Both documents are parsed and compared locally in your browser. Nothing is sent to a server, nothing is stored. This is especially important when diffing API responses or config files that may contain credentials; you can safely compare two versions of a secrets.json without ever transmitting them.
Does it do structural diff or just text diff?
It's a structural diff, not a line-by-line text diff. That means key order doesn't matter — {a:1, b:2} compared to {b:2, a:1} registers as equal. Array element moves are detected where possible, and nested objects are recursed into. You get an accurate picture of what actually changed semantically, not just what moved on screen.