JSON Diff & Compare

A JSON diff (or compare) tool reports the structural differences between two JSON documents. Instead of comparing text line by line — which is fragile when whitespace or key order changes — it parses both sides, walks the trees in parallel, and lists every key that was added, removed, or changed, with the exact JSON path to each difference.

A text diff (like git diff) compares strings. Reformatting a file, swapping the order of two keys, or changing indentation produces noise even when the data is identical. A JSON diff compares meaning: object key order is ignored by default, whitespace is irrelevant, and only real semantic differences are reported.

Every difference falls into one of three categories. 'Added' means the key or array index exists on the right but not on the left. 'Removed' means it exists on the left but not on the right. 'Changed' means it exists on both sides with different values — for example a string changed to a different string, or a number changed to a boolean.

By default arrays are compared positionally — index 0 against index 0, index 1 against index 1, and so on. When 'Ignore array order' is enabled, arrays that contain only primitives (strings, numbers, booleans, null) are compared as multisets, so [1, 2, 3] and [3, 2, 1] are reported as identical. Arrays containing objects are still compared positionally to avoid ambiguous matches.

No. JSON object keys are unordered by specification, so the diff treats { "a": 1, "b": 2 } and { "b": 2, "a": 1 } as identical. Key reordering never shows up as a difference.

Each reported difference includes a JSON path in dot/bracket notation, for example $.user.address.city or $.items[2].price. That format is compatible with JSONPath, lodash.get, and most testing libraries, so you can paste the path straight into your code to access the differing value.

No. Parsing, walking, and rendering happen entirely in your browser. Neither document is uploaded, logged, or stored, which makes the tool safe for comparing API responses, configuration files, JWT payloads, and any other sensitive JSON.

Yes. Click 'Copy report' to put a plain-text version of the differences on your clipboard. Each line is prefixed with + (added), - (removed), or ~ (changed), followed by the JSON path and the value preview — ready to paste into a pull request comment, bug report, or commit message.

Yes, within the limits of your browser's memory. The diff walks both trees in a single recursive pass and renders the result synchronously. Multi-megabyte documents compare in milliseconds; extremely large files are best diffed with a streaming command-line tool such as jq or diffson.