Free JSON Diff Tool Online
Compare two JSON objects and highlight every added, removed, and changed key — deep recursive diff, browser-only.
How it works
Paste original JSON
Put the original JSON in the left panel.
Paste modified JSON
Put the new/modified JSON in the right panel.
Compare
Click Compare or press Ctrl+Enter. Differences are listed by key path.
Review changes
Added keys are green, removed keys are red, changed values are shown before/after.
Common use cases
API response versioning
Compare two API responses from different versions to see which fields were added, removed, or changed.
Config drift detection
Compare JSON config files from two environments to identify unexpected differences.
Schema migration review
Compare JSON schemas before and after a migration to verify expected changes and catch regressions.
Test fixture diffing
Compare actual vs expected JSON in test output to understand what changed when a test breaks.
Frequently asked questions
Is this a structural or text diff?
Structural — the diff compares the parsed JavaScript objects recursively, not the raw text. Key order differences are ignored; only actual value changes are shown.
Does it handle nested objects and arrays?
Yes — the diff walks the full object tree. Nested object changes show the full key path (e.g., user.address.city changed).
How are arrays compared?
Arrays are compared index-by-index. If the arrays have different lengths, the extra elements are shown as added or removed.
Does my JSON get uploaded?
No. The diff algorithm runs entirely in JavaScript in your browser.