A JSON diff is a comparison between two JSON objects that identifies what has changed between them. The result lists every added field, every removed field, and every value that changed, along with the exact key path (using dot notation) to locate each change in the JSON structure.

What do the colors in the diff mean?

Green (+) means the field exists in JSON B but not in JSON A — it was added. Red (−) means the field exists in JSON A but not in JSON B — it was removed. Yellow (~) means the field exists in both but the value changed — the old value is shown struck through and the new value is shown next to it.

Does it support nested objects and arrays?

Yes. The diff is deep — it recursively compares nested objects at any depth and reports changes using dot-notation paths (e.g., address.city, tags[2]). Array elements are compared by index.

What does dot notation mean in the diff path?

Dot notation is a way to describe the location of a field inside a nested JSON structure. For example, address.city means the city key inside the address object. tags[1] means the element at index 1 in the tags array.

Can I use this to compare API responses?

Yes. A common use case is pasting two API responses — one from staging and one from production, or two versions of the same endpoint — and seeing exactly what changed. This is useful for debugging breaking changes in APIs.

Is my data safe to paste here?

Yes. The entire comparison runs in your browser using JavaScript. No data is sent to any server. Your JSON never leaves your device, making it safe to use with sensitive API responses or private data.

Free · Browser-only · No sign-up

JSON Diff Checker

Paste two JSON objects and instantly see every difference. Added fields highlight in green, removed in red, changed values show old and new side-by-side. Deep comparison with full nested object and array support using dot-notation paths.

Deep comparisonNested objectsArray diffDot-notation paths100% offline

json a (original)

json b (modified)

About this tool

Performs a deep structural diff between two JSON objects. Added keys show in green, removed keys in red, changed values show both the old and new value in yellow. Array elements are compared by index. Runs entirely in your browser — no data is sent anywhere.

Features

Deep comparison

Recursively diffs nested objects and arrays at any depth

Dot-notation paths

Every change shows its exact path like user.address.city

Color-coded output

Green for added, red for removed, yellow for changed values

Change summary

Count of added, removed, and changed fields at a glance

Identical detection

Clearly signals when both JSON objects are exactly the same

Browser-only

Zero server requests — your data stays on your device

How to use

1
Paste JSON A
Paste the original or baseline JSON into the left panel.
2
Paste JSON B
Paste the modified or updated JSON into the right panel.
3
Compare
Click Compare JSON to run a deep structural diff.
4
Review results
Scroll the diff panel to see every change with its exact path, old value, and new value.

Frequently asked questions

How are array differences shown?

Array elements are compared by index. If JSON A has tags[0]="developer" and JSON B has tags[0]="engineer", the diff shows tags[0] as changed. New elements added to the end show as added with their index.

What if the two JSON objects have completely different structures?

All keys in JSON A that are absent from JSON B appear as removed, and all keys in JSON B absent from JSON A appear as added. The tool handles any structural difference.

Can I compare arrays at the top level?

Yes. Paste two JSON arrays and the tool compares them element by element, showing differences at each index position.

How is this useful for API development?

Compare API responses from two environments (dev vs prod), two API versions, or before and after a deployment to spot unintended changes, missing fields, or type changes in response payloads.

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