Compare two JSON documents

Compare two JSON documents by what they hold rather than how they are written. Paste an API response from yesterday and one from today, two versions of a configuration file, or a fixture before and after a test, and the result lists each field that was added, removed or changed, with the path that leads to it.

A line-by-line diff gets JSON wrong in two directions. Reformatting a file or sorting its keys makes every line look different, so the one real change is buried. And a value that changed type, a price of 10 that became “10”, can look identical to the eye and still break the code that reads it. This comparison parses both sides first, matches object keys by name whatever their order, matches array items by position, and treats a change of type as a change.

Each line of the report starts with a sign. A plus is a field that only the changed document has, a minus is one only the original has, and a tilde is a field present in both with a different value, shown as the old value, an arrow and the new one. Paths are written the way you would reach the value in JavaScript, such as $.items[2].price, with quotes around keys that contain spaces or symbols.

Both documents have to be valid JSON. If one is not, the tool says which side and where the parser stopped, so you can fix it in the formatter before comparing. Very long values are shortened in the report to keep each line readable; the comparison itself always uses the full value.

The comparison runs in this browser tab. API responses and configuration files often hold tokens, customer records and internal addresses, and none of it leaves your device.