JSON Diff Checker
Paste two JSON documents to compare them field by field. Added, removed, and changed values are colour-coded — everything runs in your browser, so your data never leaves your machine.
About JSON Diff Comparison
Comparing two JSON documents by hand is slow and error-prone, especially when objects are deeply nested or arrays are long. A JSON diff tool walks both structures key by key and index by index, then reports exactly what changed: which fields were added, which were removed, and which values were modified. This is invaluable when reviewing API responses, debugging configuration drift, verifying data migrations, or checking what a code change did to serialized output.
How to Read the Diff:
- Added (+): Keys or values present in the right (changed) document but not in the left (original).
- Removed (-): Keys or values present in the left document but missing from the right.
- Changed (~): Keys that exist in both documents but whose values differ — shown as
old → new. - Unchanged: Identical entries, dimmed for context so you can see where changes sit within the structure.
Common Use Cases:
- API Debugging: Compare an expected response against an actual one to spot regressions.
- Config Review: See exactly what changed between two versions of a settings file.
- Data Migration: Verify that transformed records match the source before and after a migration.
- Code Review: Understand how a change affected serialized JSON output.
This tool compares objects by key and arrays by position, then colour-codes every difference. Because it runs entirely client-side, you can safely compare sensitive payloads — nothing is uploaded, stored, or tracked.