What is API Response Diff?

A free browser tool that compares two JSON API responses and highlights added fields, removed fields, value changes, and type changes. It flags contract-breaking changes that could break API consumers.

Is my data sent to a server?

No. All parsing and diffing runs entirely in your browser. Nothing is uploaded.

What counts as a breaking change?

Removed fields, type changes (e.g. number to string), and structural changes (object to array) are flagged as breaking. Added fields are generally safe for consumers.

API Response Diff - Compare JSON Endpoints, Detect Breaking Changes

0Added

0Removed

0Changed

0Type

Before (baseline)

{
  "id": 1,
  "name": "Ada Lovelace",
  "email": "ada@example.com",
  "plan": "free",
  "limits": {
    "requests": 100,
    "storage_mb": 50
  },
  "roles": ["user"],
  "created_at": "2026-01-15T08:00:00Z"
}

After (new version)

{
  "id": "usr_1",
  "name": "Ada Lovelace",
  "email": "ada@example.com",
  "plan": "pro",
  "limits": {
    "requests": 5000,
    "storage_mb": 500,
    "bandwidth_gb": 100
  },
  "roles": ["user", "admin"],
  "active": true,
  "created_at": "2026-01-15T08:00:00Z",
  "upgraded_at": "2026-06-01T12:00:00Z"
}

Path-level changes

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