# JSON Diff Checker

> Free JSON diff tool. Paste two JSON documents and see added, removed, and changed keys side by side. Runs entirely in your browser, nothing is uploaded.

Spot every difference between two JSON documents. Free, no sign-up, fully private.

*Interactive tool: enter your values at https://toollantern.win/json-diff-checker/ and results update instantly in your browser.*

## What it does

Paste the old JSON on the left and the new JSON on the right, then compare. The tool flattens nested objects into dotted key paths and lists every added, removed, or changed value in a color-coded table with a summary count.

## Common uses

Checking what an API response changed between versions, reviewing config edits before deploy, or spotting accidental edits in a JSON file.

## Private by design

Parsing and comparison happen locally in JavaScript. Nothing you paste ever leaves your device.

## Frequently asked questions
### Does it handle nested objects?

Yes. Nested keys are flattened to dotted paths like address.city, so deep changes are easy to spot.

### What about arrays?

Arrays are summarized by length (for example [array:3]) rather than compared element by element.

### Is my JSON sent to a server?

No. Everything happens in your browser.

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Interactive version: https://toollantern.win/json-diff-checker/