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JSON Diff Checker

Compare two JSON objects side by side. See exactly which keys were added, removed, or changed - including deeply nested differences.

About JSON Diff Checker

The JSON Diff Checker performs a deep structural comparison between two JSON values. Unlike a simple text diff, it understands JSON structure - so reordering keys in an object doesn't show as a change, and it drills into nested objects and arrays to find the exact differences.

How to Read the Output

  • Green (added) - Key exists in JSON B but not in JSON A.
  • Red (removed) - Key exists in JSON A but not in JSON B.
  • Yellow (changed) - Key exists in both but has a different value.
  • Grey (unchanged) - Key exists in both with the same value.

How to Use

  1. Paste the first JSON into the left panel.
  2. Paste the second JSON into the right panel.
  3. Click Compare - differences are highlighted instantly.
  4. Added keys are shown in green, removed keys in red, changed values in yellow.

How It Works

Both JSON objects are parsed and then recursively compared key by key. The diff engine identifies keys that exist in only one object (additions/deletions) and keys that exist in both but with different values (modifications). Nested objects are compared recursively.

Example

Compare two versions of a config file to see what changed between deployments: API endpoint changed, new feature flag added, deprecated setting removed - all shown clearly side by side.

FAQ

No. This tool compares JSON semantically. {"a":1,"b":2} and {"b":2,"a":1} are considered identical because JSON objects are unordered by definition.
Arrays are compared element by element using their index. [1,2,3] vs [1,3,2] would show index 1 and 2 as changed. Array order does matter for this comparison.
Yes. The diff recursively descends into nested objects and arrays, showing the full path (e.g., address.city) for each difference.
No. All comparison happens entirely in your browser using JavaScript. Your data never leaves your device.