How to use the JSON Diff Checker
- 1. Paste the originalPut the old or expected JSON on the left.
- 2. Paste the new onePut the changed or actual JSON on the right.
- 3. CompareSee each difference with its path and both values.
How the comparison works
Text diff tools compare lines, so reformatting or reordering keys makes everything look different. This tool parses both documents and compares the data, so spaces, line breaks and key order are ignored. It walks both structures together and reports three kinds of change:
- added: a key or array item that only exists in the changed JSON.
- removed: a key or item that only exists in the original.
- changed: the same path with a different value or type, such as 24 vs "24".
Paths are written the way you would access them in JavaScript, such as user.address.city or skills[2].
Worked example
In the sample, Asha's record changes between two API responses. The tool finds 4 differences: 2 added, 1 removed, 1 changed:
- changed
age: 24 → 25 - added
skills[2]: "Power BI" - removed
city: "Noida" - added
email: "asha@example.com"
Unchanged fields like name and active are not listed. Typical uses: checking what an API change did to a response, comparing config files between environments, and debugging failed tests that compare JSON.
Arrays are compared position by position. If one item is inserted at the start, every later item shifts and shows as changed, so sort arrays first when their order does not matter.
Frequently asked questions
Does key order matter?
No. {"a":1,"b":2} and {"b":2,"a":1} are treated as identical.
Is 1 the same as "1"?
No. A number and a string are different JSON types, so it is reported as changed.
Is my data uploaded?
No. Both documents are compared in your browser.
Is the json diff checker free?
Yes, it is free. Your first comparison asks for your name and WhatsApp number once, and after that the json diff checker and every other Uncodemy tool open without the form.