Paste two JSON texts and get the added, removed and changed values by path, plus a JSON Patch. Nothing is uploaded.
A JSON diff compares the meaning of two JSON texts, not their lines, and lists every value that was added, removed or changed at its JSON Pointer path, such as /owner/id. Both texts are parsed first, so spacing, line breaks and the order of keys in an object never count as a change. Objects are compared key by key, lists item by item, and everything else value by value. A value with a different type, such as the number 7 against the string "7", is reported on its own as a type change, because code that reads it will behave differently. The number 1 and the number 1.0 are the same value in JSON, so they are never reported. Each line of the change list starts with a sign: + for added, - for removed, ~ for changed.
Take {"version": 1, "tags": ["a", "b"], "owner": {"id": 7}, "legacy": true} and change it to {"version": 2, "tags": ["a", "b", "c"], "owner": {"id": "7"}, "beta": true}. The page lists five differences. /version changed from 1 to 2. /tags/2 was added with the value "c". /owner/id changed type from number to string. /legacy was removed and /beta was added. The page opens with a longer sample of the same kind, so you can see this result before you paste anything.
By default list items are compared by position, so moving one item to the front of a ten item list changes up to ten positions. Turn on Ignore array order to match items wherever they sit: plain values match as a multiset, so two copies of 3 need two copies on the other side, and objects match when every key and value is equal. Turn on Ignore letter case in strings to treat "Yes" and "yes" as equal; keys are always compared exactly. With array order ignored, an object that changed inside a list shows as one removal and one addition, because the page does not guess which object became which.
The second output is a JSON Patch as defined in RFC 6902: a list of add, remove and replace operations that turns the original into the changed JSON when they are applied in order. Removals inside a list run from the last index to the first so earlier positions stay valid. With Ignore array order on, the patch makes the lists equal as sets of items and appends new items at the end, so it does not reproduce the order of the changed list. Move operations are not generated; a moved value shows as a removal and an addition.
Each box is checked on its own and a problem is reported as Original or Changed, then the line and column, such as Line 3, column 5. The rules are strict JSON: no comments, no trailing commas, double quotes only. Numbers are read as JavaScript numbers, so integers beyond 9,007,199,254,740,991 lose precision before they are compared, and a key that appears twice in one object keeps its last value. Each text can be up to 500,000 characters. The list stops at 5,000 differences, and then no patch is made. Everything runs in this tab.
Paste the first file into the Original box and the second into the Changed box. The page lists every difference by path, for example ~ /version: 1 -> 2, and counts additions, removals, changes and type changes. Nothing needs to be uploaded.
In JSON an object is an unordered set of keys, so {"a":1,"b":2} and {"b":2,"a":1} hold the same data. Key order is ignored on this page and cannot be switched on. List order does matter by default, because a list is ordered.
Turn on Ignore array order. Then [1, 2, 3] and [3, 1, 2] are equal, and [1, 1, 2] differs from [1, 2] by one extra 1. Objects in a list match when all of their keys and values are equal.
It is the same change set in the RFC 6902 format, such as {"op": "replace", "path": "/version", "value": 2}. Libraries in most languages can apply it to the original document to produce the changed one. Paths use ~0 for ~ and ~1 for / inside a key.
One is a number and one is a string, and code that checks the type treats them differently. The page counts those separately under Type changed so you can find API changes that keep the same digits.
No. The text is processed in your browser and not uploaded. Your two JSON texts are never saved; only the two option settings are kept on this device.