Compare JSON Online
A JSON compare tool reads two JSON documents and reports back every place they differ: keys present on one side and not the other, values that changed, items added or removed inside arrays, and how similar the two payloads are overall. The result is a structured diff you can read path by path, plus a deep merge, a key audit, and an RFC 6902 patch that can be replayed against the original document to reproduce the change.
Right before a release, you need to see what shifted between two versions of a payload and the first move is pasting them side by side in a text editor. That stops working once the file runs past a single screen. Our JSON Compare shows every changed key, missing field, and moved array item path by path, and generates an RFC 6902 patch you can replay.
Diffing Two JSON Documents in Four Steps
- Load the left and right panels: paste, drop a .json file onto either panel, or click Upload to load each side.
- Choose an analysis mode: pick JSON Diff, Structure View, Key Analysis, Merge JSON, Patch Generator, or Semantic Diff from the sidebar.
- Read the report: the result pane shows colour-coded paths, counts, a merged payload, an RFC 6902 array, or a similarity percentage.
- Swap or export: hit Swap to flip the sides, Copy to grab the result, or Download to save the merged JSON or patch file.
What You Can Do with JSON Compare
Path-by-Path Diff
Walk both trees in parallel and tag every path added, removed, changed, or unchanged.
Side-by-Side Structure
Pretty-printed twin panels with root type and top-level key counts for a fast visual scan.
Shared and Unique Keys
Flatten every dot and bracket path into shared, left-only, and right-only buckets.
Deep Merge with Priority
Recursively merge objects with right-side wins, ready to copy or download as JSON.
RFC 6902 Patch
Generate an add, remove, and replace operation array for use with any JSON Patch library.
Similarity Score
Get a single percentage plus a colour-coded chart of matched, added, removed, and changed paths.
Why Choose AIFreeForever's JSON Compare
| Feature | AIFreeForever | Typical Online Tools |
|---|---|---|
| Modes Bundled | Diff, structure, keys, merge, patch, similarity | Line diff only |
| RFC 6902 Output | Copy or download a ready-to-apply patch | Not supported |
| Deep Merge | Recursive object merge with right-side priority | Hidden behind a paid plan |
| Privacy | Both payloads parsed in the browser | Uploaded to a remote server |
| Input Methods | Paste, upload, or drag and drop per panel | Paste only |
Trusted by API Maintainers, Config Reviewers, and QA Teams
When two response payloads should match but something has drifted, our JSON Compare shows you which field moved and where. You can paste old and new config manifests before a deploy and see every changed key, or generate an RFC 6902 patch so a failing fixture replays against the baseline without you writing the operations by hand.
Clearest way to spot what changed between two payloads
Drop both documents in once and switch between path diff, structure view, key audit, deep merge, RFC 6902 patch, and similarity score from the same panel without re-uploading or sending your JSON to a server.
Colour-Coded Path Diff
Added, removed, changed, and matched paths grouped by status for a quick read.
Replayable Patches
Standards-compliant RFC 6902 output ready for fast-json-patch and friends.
Stays in the Browser
Both documents parse locally, nothing is uploaded or stored anywhere.
