Compare two JSON payloads and visualize every difference — added, removed, and changed fields.
This tool helps you compare two JSON structures side by side and instantly see every difference. Follow these steps to get started:
Ctrl+Enter keyboard shortcut. The diff results appear instantly in the panel below.This tool uses a Longest Common Subsequence (LCS) algorithm for arrays, which intelligently matches unchanged items even when elements are inserted or deleted in the middle. For objects, it compares keys and values recursively. This produces accurate, human-readable diffs even for complex nested structures.
No. All JSON comparison happens entirely in your browser using JavaScript. Your data never leaves your computer. This makes the tool safe for comparing sensitive or proprietary JSON payloads.
The tool validates JSON in real time as you type. If either side contains invalid JSON, a red status dot appears with an error message, and the Compare button will show an error. Fix the syntax issues and the tool will become ready to compare again automatically.
Yes, but very large arrays (over 2000 elements) fall back to index-by-index comparison instead of the LCS algorithm to prevent memory issues. For extremely large JSON files, consider using the Format buttons to prettify the output first for easier manual review.
Green badges/values indicate added content, red indicates removed content, and gold/yellow indicates modified content. The diff tree also uses blue "nested" badges for container nodes that have multiple child changes, with the count of changes shown in the badge.