Paste two JSON documents — one in each panel — and see the differences highlighted instantly. Added lines are shown in green, removed lines in red. The toolbar shows whether the two documents are semantically identical or have differences.

The tool runs two types of comparison simultaneously:

Visual diff — compares the raw text line by line, the same way git diff does. Added lines are highlighted green, removed lines red. This is useful for spotting exactly which lines changed, including whitespace and key order.

Semantic diff — parses both documents and compares the actual data values. Two documents that are visually different but represent the same data — different key ordering, different indentation, trailing zeros — will show as Identical in the toolbar badge.

Example: These two documents are visually different but semantically identical:

{ "name": "Alice", "age": 30 }

{
  "age": 30,
  "name": "Alice"
}

The visual diff will show every line as changed. The semantic badge will say Identical — because the parsed data is the same.

Paste the API response from staging and production side by side to find environment-specific discrepancies. The diff shows exactly which fields differ without manual scanning.

For config reviews, comparing two versions of package.json or tsconfig.json here is faster than reading a git diff when the file is deeply nested. After a data migration, compare a sample record from source and destination to verify the transformation is correct.

API versioning is another natural fit — put the v1 and v2 response schemas side by side to document exactly what changed for consumers. For debugging webhook issues, two events that should be identical often have one differing field; the diff finds it in seconds.

Format before comparing — if both documents are minified, the visual diff shows everything as one big changed line. Use the JSON Formatter tool to pretty-print both sides first, then paste them here for a clean, readable diff.

Use Swap to reverse direction — the diff is directional: left is "original", right is "modified". If you pasted them the wrong way around, click Swap to reverse without re-pasting.

Edit either side live — both panels are editable. You can fix a typo or adjust a value on one side and watch the diff update instantly, without needing to repaste.

Semantic Identical ≠ no changes — if the badge shows Identical but the visual diff shows changes, it means the data is the same but formatted differently (key order, indentation). This is safe to ignore for data comparison purposes.