JSON Diff Checker
Diff two JSON documents with path-level change listing — spot breaking API changes instantly. Review a 500-line response diff in minutes — local processing, free, no signup.
How to Use the JSON Diff Checker
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Frequently Asked Questions
How do I spot breaking API changes?
Diff old vs new response: removed fields and type changes break clients, added optional fields don't. Review the path list before approving the backend deploy.
Key order differences?
Ignored by default — JSON objects are unordered, so reordered keys aren't changes. Enable strict order mode only for canonical-form checks.
Large payloads?
Thousand-line payloads diff fine locally; collapse unchanged regions to focus. Save both versions for the PR record.
Is payload data uploaded?
No — diffing runs locally in your browser. Payloads never leave your device.
What does a one-value change print as?
With the defaults ({"a":1,"b":2} vs {"a":1,"b":3}) the output is exactly 2 lines: `- b: 2` then `+ b: 3`. Nested objects recurse with dot-joined paths, array elements get [i] suffixes, unparseable input toasts Invalid JSON in one or both inputs, and identical docs print (no differences).
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Last updated October 2026