JSON Diff & Compare
Paste two documents. Key order never counts, array items are matched by id — you only see real changes.
A JSON compare that shows only what matters
Built for comparing API responses, configs and fixtures — without the noise of text-based diff tools.
- Structure, not text
- Reordered keys and different formatting never show up as changes.
- Smart array matching
- Items are paired by id, uuid, sku… so inserting one item doesn’t flag the whole list.
- Ignore the noise
- Skip timestamps and request IDs anywhere with wildcards like *At — with one-click suggestions.
- Readable paths
- Every change shows its exact location, like $.users[id=42].email — click to copy.
- Reports & patches
- Copy a Markdown table for a ticket or PR, or a standard JSON Patch for code.
- Private & free
- Runs in your browser. Big numbers stay exact. Free AI summary on-device.
Frequently asked questions
Why does this find fewer differences than other JSON compare tools?+
Most tools compare text line by line, so reordered keys or one item inserted at the top of an array make everything look changed. CurlyJSON compares structure: key order never counts, and array items are matched by their id (or by content), so you only see real changes.
How are array items matched?+
Smart mode looks for a field that uniquely identifies every item — like id, uuid, sku or userId — and matches items by it, wherever they are in the array. Without one, it aligns unchanged items and reports only what was inserted, removed or edited. You can also pick a key yourself, compare strictly by position, or ignore order completely.
Can I ignore timestamps and request IDs?+
Yes. List field names in “Ignore fields” — wildcards work, so *At ignores createdAt and updatedAt everywhere. CurlyJSON also suggests fields that look like timestamps when they change.
Is my data uploaded?+
No. Both documents are compared in your browser. Share links keep the data after the # in the URL, which is never sent to a server. The on-device AI summary also runs locally in desktop Chrome.
What is the JSON Patch output?+
A standard RFC 6902 patch: a list of add, remove and replace operations that turns the original document into the modified one exactly. Use it in APIs, tests, or to store changes compactly.