JSON Diff Checker

Format both sides first

This is a text-based diff, which means it compares line by line. JSON that arrives as a single minified line will diff poorly, because the whole document is one line. The trick is to pretty-print both versions with the same indentation before comparing, so each key sits on its own line:

{
  "id": 42,
  "active": true,
  "price": 9.99
}

Once both sides are formatted identically, the diff becomes beautifully readable: a changed value shows as one red line and one green line, an added key appears as a single green line, and a removed key as a single red line. Our JSON Formatter will pretty-print and sort both documents in one click.

Sort keys to compare by content

JSON objects have no guaranteed key order, so two objects that are semantically identical can list their keys differently. A line diff treats that as a change. The fix is to sort keys alphabetically on both sides before diffing — then only genuine content differences remain. Sorting also stabilises the output so re-running the comparison always lines up the same way.

If you would rather not reorder, you can lean on the ignore options instead, but sorting first gives the cleanest, most trustworthy JSON diff.

What the diff reveals

Use character granularity to pinpoint a one-digit difference in an id or a flipped boolean, and read the similarity percentage to gauge how much the two payloads diverge overall.

Private and offline-friendly

API payloads frequently contain tokens, customer records and internal identifiers, so pasting them into a server-side comparator is risky. This checker keeps everything local: the comparison runs in your browser and nothing is uploaded. You can compare production data, webhook bodies and secrets safely, and the page keeps working with no connection once it has loaded.