JSON Compare

What is JSON Compare?

Paste two versions of a JSON document and see a line-by-line diff, useful for reviewing an API response change or spotting what a script modified. A common use case: comparing an API response before and after a backend change, or checking what a data migration script actually altered. The diff runs entirely in your browser, so nothing you paste, including a real API response, is sent to a server.

How to Use JSON Compare

1. 1

   Paste Both Versions: Enter the original JSON on one side and the updated version on the other.

2. 2

   Read the Diff Instantly: Added, removed, and changed lines are highlighted automatically.

How It Works

This is a line-by-line text diff, not a structural JSON comparison. Both inputs are split into lines and compared the way a code diff tool would: each line is marked unchanged, added, or removed based on whether it appears in the same relative position in both documents. Because it works on text rather than parsed JSON, two documents that are semantically identical but formatted differently (different indent width, different key order) will show as different. Pretty-print both sides with matching settings first if you only care about value changes.

Example

The "name" line is flagged as changed, "active" as removed, and "role" as added, while "id" stays unchanged.

What Kind of Differences It Surfaces

Any line-level edit: a changed value, a renamed or removed key, a newly added field, or a line that shifted position. It won't tell you "the value at path $.user.role changed" the way a schema-aware JSON diff would. It tells you which lines of text differ, which is usually enough for reviewing an API response or a config change.