JSON Diff & Compare

Compare two JSON documents by structure — see added, removed & changed keys.

Compare two JSON files or objects and see exactly what changed — added, removed and modified keys, side by side. Free, in your browser, nothing uploaded.

About JSON Diff & Compare

JSON Diff & Compare is a free tool that compares two JSON documents by structure and lists every key, index, and value that was added, removed, or changed. It walks both documents recursively, ignores object key order, and compares arrays by position, showing each difference as a JSONPath-style location like config.retries or tags[0]. Everything runs in your browser — both documents are parsed and compared locally with no signup and no upload.

How to use JSON Diff & Compare

  1. Paste the original JSON into the Left (original) box and the updated JSON into the Right (updated) box — or click Load sample to try it with example data.
  2. Both sides parse live as you type; if either side is invalid, fix the JSON on the highlighted side using the inline parser error.
  3. Read the summary stats (Added, Removed, Changed, Total) and the color-coded groups, each listing the exact path and value that differs.
  4. Use Swap sides to reverse old and new, or Clear to start over.
  5. Click Copy diff to copy a plain-text summary, or Download to save it as json-diff.txt for a pull request or commit note.

Frequently asked questions

Are my JSON documents uploaded anywhere?
No. Both documents are parsed and compared entirely in your browser using JavaScript — nothing is sent to a server, and no file ever leaves your device.
Is it free and do I need an account?
Yes, it is completely free with no signup, no account, and no usage limits.
How does the comparison work — does key order matter?
It compares by structure, not text. Object key order is ignored, so reordered keys are not flagged as changes, while arrays are compared positionally by index. Each difference is reported as a JSONPath-style location such as config.backoff or tags[1].
What counts as added, removed, or changed?
Keys or array indices present only on the right are Added, those present only on the left are Removed, and a leaf whose value differs is Changed. When one side is an object or array and the other is a scalar (or an array vs an object), the whole node is reported as a single Changed entry.
Is there a size limit?
Yes. Each side is capped at roughly 2 MB so an oversized paste can't freeze the tab. Larger inputs show a warning and are not compared.
What if my JSON is invalid?
Each side is validated with the browser's native JSON parser as you type. If a side is malformed, you'll see an inline error message (with the parser's position info when available) and the diff waits until both sides are valid JSON.

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