What does the diff show?

Three categories: ADDED (path exists in B but not in A), REMOVED (path exists in A but not in B), CHANGED (path exists in both but with a different value or type). Each entry shows the full dot-notation path so you know exactly where the difference lives.

How are arrays compared?

Index-by-index. arr[0] is compared with arr[0] in both versions. If lengths differ, extra elements show up as added/removed at their indices. Order-sensitive — moving an element counts as a change at that index.

Is the diff order-sensitive for object keys?

No — objects are compared by key, not by insertion order. The same object with keys in a different order produces zero diffs.

Can I diff two API responses?

Yes — that's the most common use case. Snapshot a known-good response as JSON A, paste a fresh response as JSON B, see what changed. Useful for catching breaking API changes.

What if the JSONs are huge?

The diff runs in your browser, so the practical ceiling is your device's memory. Tens of thousands of entries process in well under a second on most devices.

Is the data sent to a server?

No. Both JSONs and the diff result stay on your device. Safe to compare production responses, internal API contracts, or sensitive payloads.

How does this differ from a text diff?

Text diff (line-by-line) treats reordered keys, whitespace changes, and indentation as differences. Structural JSON diff ignores all of those — it only flags meaningful changes to data. Much cleaner signal.

Are type changes flagged separately from value changes?

Yes. A path that changes from "42" (string) to 42 (number) shows up as a CHANGED entry with both old and new values visible, so type drift is impossible to miss — common gotcha when an API starts returning numbers as strings.

JSON Diff — Compare Two JSONs Free Online

Free online JSON diff tool — compare two JSON values structurally and see added, removed, and changed paths in seconds. Browser-based, no signup.

Compare two JSON values structurally and see exactly what changed — added paths, removed paths, and changed values, all with their full dot-notation paths. PDFFlare's JSON Diff is a structural comparison, not a text diff: reordering object keys produces zero noise.

Already know one of the JSONs is broken? JSON Formatter validates and pinpoints parse errors. Want to query a specific path instead of seeing every diff? JSONPath Tester extracts targeted values.

JSON A

JSON B

A:0 lines · 0 B|B:0 lines · 0 B

How to Compare Two JSONs

Paste JSON A and JSON B
Drop two JSON values into the side-by-side editors. They can be objects, arrays, or any valid JSON.
Click Compare
PDFFlare walks both trees in lockstep and shows every added, removed, and changed path with the affected values.
Read the diff
Each entry shows the path (a.b[0].c), the change type, and the relevant values. Counts in the header bar give you the at-a-glance summary.

When Do You Need to Diff JSON?

Catching breaking API changes: The vendor pushed an update overnight. Snapshot yesterday's response, diff against today's, see what fields they renamed or removed before your code crashes.

Code review for config changes: Reviewing a 5000-line JSON config in a PR is brutal. Diff the before/after structurally to see only the meaningful changes.

Comparing test fixtures: Snapshot tests sometimes fail in confusing ways. Diff the expected and actual JSON to see exactly which path regressed.

Debugging: “Why is the response different from staging?” Paste both, diff, get a precise list of paths that diverge.

Why Use PDFFlare for JSON Diff?

Structural, Not Textual

Reordered keys and indentation differences don't pollute the output. You see only paths whose values actually differ.

Color-Coded Summary

Counts of added / removed / changed are visible at a glance. Each entry is colour-coded so you can scan hundreds of changes quickly.

100% Browser-Based

Both JSONs and the diff stay on your device. Safe for production payloads or internal API contracts.

No Signup Required

Open, paste both sides, click Compare. No account, no rate limits.

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