JSON Diff Tool Online
Compare two JSON objects online, find changed keys, missing fields, and value differences with a private browser-based JSON diff tool.
Compare JSON
About this online JSON diff tool
This JSON diff tool compares two JSON objects and shows added, removed, and changed values by key path. It is built for API debugging, webhook testing, configuration reviews, feature flag checks, mock data updates, and documentation examples.
Paste the original JSON on the left and the changed JSON on the right. The comparison flattens nested objects into readable paths, making it easier to spot changed keys without manually scanning large payloads.
The diff runs in your browser, so test data is not sent to an external service. Always remove secrets, tokens, and private customer data before pasting anything into a web page, even when a tool is browser-based.
JSON comparison tips
Format both objects before comparing when you need to review structure visually. If the tool reports invalid JSON, check for trailing commas, comments, single quotes, or copied smart quotes. For arrays, remember that order can matter depending on the API or test fixture.
FAQ
Is this tool free?
Yes. It is free to use on FreeToolsSpace and does not require sign-up.
Does the tool upload my files or text?
The core action runs with JavaScript in your browser. Avoid pasting information you should not process in any web page.
Can I use it on mobile?
Yes. The layout is responsive and works in modern mobile browsers.