JSON Compare — Diff Two JSON Documents

Comparing JSON the right way

Raw text diffs lie about JSON: a reordered key, a re-indented block, or a trailing-comma cleanup lights up the whole file in red while changing nothing semantically. The fix is normalization — parse both documents, sort their keys, serialize them identically — and only then diff. This tool builds that workflow into two buttons: Compare (format both) and Sort keys (normalize ordering), and the underlying rule is RFC 8259 itself: object member order is not significant, so a diff that treats reordering as a change is reporting noise.

The diff itself is VS Code's: changed lines highlighted side by side, intra-line changes emphasized, unchanged regions foldable. The status bar's changed-region count gives you the one number a review needs. Sort both sides with the JSON sorter before comparing when the producers serialize keys in different orders; for YAML manifests or XML configs, the YAML diff and XML diff pages use the same side-by-side engine with format-aware highlighting. Once you've found what changed, RFC 6902 JSON Patch is the machine-readable way to describe the same edit as a list of operations, if a diff needs to be applied programmatically rather than just read.

A worked comparison

An order status update, shown left (before) and right (after): the status field changed, a trackingNumber key was added, and the customer object's keys were reordered without any value changing.

Compare highlights three regions: the status line, the new trackingNumber line, and — because Sort keys was not used here — the reordered customer keys, even though id and name still hold the same values. Running Sort keys on both sides first removes that third region entirely and leaves only the two changes that matter.

{
  "orderId": "ORD-4471",
  "status": "processing",
  "customer": {
    "id": "cus_88f2",
    "name": "Elena Petrova"
  },
  "items": [
    { "sku": "SKU-1", "qty": 2 }
  ],
  "total": 84.50,
  "currency": "USD"
}

{
  "orderId": "ORD-4471",
  "status": "shipped",
  "customer": {
    "name": "Elena Petrova",
    "id": "cus_88f2"
  },
  "items": [
    { "sku": "SKU-1", "qty": 2 }
  ],
  "currency": "USD",
  "total": 84.50,
  "trackingNumber": "1Z999AA10123456784"
}

Typical comparison workflows

Config drift: paste production config left, staging right, sort keys, and read the real differences in seconds. API versioning: capture a response before and after a deploy and verify only the intended fields moved. Data debugging: paste an expected fixture against an actual payload to find the field that broke a test.