JSON Diff

What this does

Compares two JSON values semantically and surfaces every difference, deeply.

For each difference the diff shows:

• The exact path into the structure (e.g., user.address.postalCode or roles[2])
• The kind of change: added (only on right), removed (only on left), or changed (both, but value differs)
• The left value, the right value

The comparison ignores key ordering. {"a": 1, "b": 2} and {"b": 2, "a": 1} are equal here — they’re the same JSON document.

What this is for (and why a regular text diff is not enough)

A line-based text diff treats {"a":1,"b":2} and {"b":2,"a":1} as different. It also treats {\n "a": 1\n} and {"a":1} as different (whitespace + line breaks). Neither is what you want when you’re trying to answer “did the data change?”

This tool answers the data question. Whitespace, key order, indentation — none matter.

Specific cases this helps with:

• API regression checks. “Did our API response actually change between yesterday and today?” Hit the endpoint twice, paste both, see the structural delta.
• Reviewing a config diff. Two tsconfig.json or package.json versions: did dependencies actually change, or just reordering from npm install?
• Test snapshot triage. A snapshot test failed. Was it a real change or formatting? Paste old vs new.
• Reviewing AI-generated edits. When a coding assistant rewrites a JSON file, this shows what actually changed in the data, ignoring its formatting choices.
• Migration verification. “Did the upgrade script preserve all the data?” Diff the before-upgrade dump and after-upgrade dump.

Edge cases handled correctly

• Type changes — if a field went from "42" (string) to 42 (number), it’s reported as changed (since the JS values differ), not as a no-op.
• Null vs missing — {"x": null} vs {} is reported: x was removed in the second (the key is gone), not just nulled. This matters because null and absent are semantically different in many APIs.
• Array element addition — extending an array reports each new index as added, with the value.
• Mixed types in arrays — handled. Each index compared independently.
• Unicode keys / special characters — pass through as JSON-quoted in the path display.

Privacy

Both JSON values stay in your browser. Nothing is sent anywhere.

Related tools