JSON Diff

A JSON diff tool compares two JSON documents and reports exactly what changed, classifying each difference as an added key, a removed key, or a changed value. Eyeballing two JSON blobs side by side is slow and error-prone, especially when they are deeply nested or thousands of lines long. This tool walks both structures recursively and lists every difference by its full path, such as $.user.address.city, so you can see at a glance what moved without scanning the raw text. The comparison follows JSON semantics rather than text semantics, which matters. Object keys are matched by name, not by position, so reordering keys in an object produces no diff. That is correct, because in JSON the order of object members is not significant. Arrays, however, are compared by index: the element at position 0 on the left is compared with position 0 on the right, and so on. This is a common gotcha. If you insert one element at the start of an array, every following element shifts by one index, and an index-based diff reports the whole tail as changed even though the values simply moved. When you care about set membership rather than order, sort both arrays the same way before diffing. Type changes are flagged as changes too: a value of 5 (number) versus the string "5" at the same path is reported as changed, not equal, which catches subtle serialization bugs where a field silently switched type between API versions. The diff is purely structural and value-based; it does not attempt fuzzy or semantic matching of moved objects. Everything runs locally in your browser, so payloads containing tokens, personal data, or internal fields are never uploaded.