Compare and diff two JSON objects. Fast, secure, and completely free. All processing happens in your browser — no data is sent to any server.
JSON Compare parses two JSON documents and reports the actual semantic differences between them — which keys were added, removed, or changed value — rather than treating them as plain text and flagging every line that shifted position. This distinction matters because JSON doesn't guarantee key order carries meaning, and a plain text diff will show a huge, noisy changeset if someone simply reordered keys or re-indented the file, even though the underlying data is identical. A structural comparison instead walks both object trees and reports only the differences that actually change what the JSON represents.
Comparing two API responses, two versions of a config file, or the expected vs. actual output of a test almost never benefits from a plain text diff, because reformatting or key reordering creates false positives that bury the real change. A structure-aware comparison cuts straight to what matters: did a value actually change, was a field added or removed, did an array gain or lose an item — which is exactly the question you're usually trying to answer when debugging a regression or reviewing a config change.
By default it flags reordering as a difference since some tools do rely on key order, but you can toggle 'Ignore key order' to treat objects with identical keys and values as equal regardless of their order.
Array order is treated as significant by default, since [1,2,3] and [3,2,1] are genuinely different sequences; the diff shows exactly which index positions differ.
These are compared by their parsed numeric value, so 1.0 and 1 are treated as equal since JSON itself doesn't distinguish between them semantically.
A text diff flags every line that moved, even from harmless reformatting; this tool understands JSON's actual structure, so only genuine data differences are reported.
No, parsing and comparison both happen locally in your browser using JavaScript.