📖 What is JSON Diff?
JSON Diff compares two JSON structures and highlights exactly what changed — added keys, removed keys, modified values and type changes. Paste JSON A on the left and JSON B on the right to see a clear, color-coded diff. Use it to compare API responses between versions, verify config changes, or debug data transformation pipelines. All processing happens in your browser.
💡 Example
Input
{"name":"Alice","age":30,"city":"NYC"}
Output
{"name":"Alice","age":31,"city":"London"} — age: 30→31, city: NYC→London
🛠️ Common Use Cases
- Comparing API responses between staging and production
- Verifying config file changes before deploying
- Debugging data transformation pipeline output
- Checking what changed in a database record between snapshots
- Reviewing JSON schema changes across API versions
📝 What Gets Compared
- Added keys — keys present in JSON B but not in A
- Removed keys — keys present in A but not in B
- Changed values — same key, different value or type
- Nested objects — recursively compared at every level
- Array elements — compared by index position
⚠️ Common Mistakes
- Key ordering — JSON objects are unordered; {"a":1,"b":2} equals {"b":2,"a":1}. This tool compares values, not key order.
- Floating point precision — 0.1+0.2 may appear as 0.30000000000000004 in one response. Normalize before comparing.
- Comparing arrays of objects — arrays are compared by index, not by a unique ID field. Reordered arrays show as completely different.
❓ Frequently Asked Questions
Does key order matter? ▾
No — JSON objects are unordered by specification. This tool compares by key name and value, regardless of order.
Can it compare nested JSON? ▾
Yes — the comparison is recursive. Nested objects and arrays are compared at every depth level.
What about large JSON files? ▾
Files up to a few MB work fine in the browser. For very large files (10MB+), the comparison may be slow.
Is my data private? ▾
Yes — all processing runs entirely in your browser. Your data is never sent to any server.
Is this tool free? ▾
Completely free — no login, no usage limits, works offline once loaded.
Yes — completely free, no login required, no usage limits.
Is my data private? ▾
Yes — all processing runs in your browser. Your data is never sent to any server.
Does it work offline? ▾
Yes — once the page is loaded, the tool works without an internet connection.