JSON Diff (Compare)
Compare two JSON objects and list the keys that were added, removed, or changed between them. Paste the second JSON after a line containing only ===
About this tool
Compare two JSON objects and list the keys that were added, removed, or changed between them. Paste the second JSON after a line containing only ===
Example
Input: {"a":1}\n===\n{"a":2,"b":3}
Output: ~ changed: a, + added: b
Privacy
This tool runs entirely in your browser. Your data is processed locally and never uploaded to a server.
How to use this tool
- Paste the first JSON object into the input area.
- Add a line containing only ===.
- Paste the second JSON object below that line.
- Run the diff to see which keys were added, removed, or changed.
Step by step, what happens
- The tool reads the text above === as the first JSON object and the text below === as the second JSON object.
- It parses both inputs as JSON and compares their keys and values.
- It marks keys that exist only in the second object as added.
- It marks keys that exist only in the first object as removed and keys with different values as changed.
Worked example
Compare an older user profile JSON with a newer one to see what changed.
Input: {"name":"Ava","role":"admin"}
===
{"name":"Ava","role":"editor","active":true}
- The tool reads the first JSON object with name and role.
- It reads the second JSON object and sees that active was added and role changed.
- It compares the values key by key and lists the differences.
Output: Added: active
Removed: none
Changed: role
Tips and common mistakes
- Make sure the separator line contains only ===, with no extra spaces or text.
- Use valid JSON in both parts, including double quotes around keys and string values.
- If you compare nested objects, the tool reports differences by keys, so keep the structure consistent between versions.
- If a key appears in one JSON but not the other, check whether it was really removed or if it was renamed.
Frequently asked questions
How do I enter two JSONs?
Paste the first, a line with only ===, then the second.
Is it a deep diff?
It compares top-level keys and reports added/removed/changed; nested values are compared by their JSON string.
Is data uploaded?
No, comparison is local.
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