What changes does the tool highlight?

Added keys (in the right document but not the left), removed keys (in the left but not the right), and changed values (same key, different value). Unchanged keys are shown without colour.

Does it handle deeply nested JSON?

Yes — the diff is recursive. It drills into nested objects and arrays to find the exact property that differs rather than marking the entire parent as changed.

What is the difference between data compare and schema compare?

Data compare diffs actual JSON values. Schema compare diffs JSON Schema definitions (structural rules). Use data compare for API payloads; use schema compare for API contracts.

Is my JSON data private?

Yes. All comparison runs in your browser — your JSON is never sent to any server.

Compare JSON Online Free — JSON Diff Tool

Online JSON Diff Tool — Compare JSON Instantly

Comparing two JSON documents by eye is tedious and error-prone — a single changed value buried in a deeply nested object can be almost impossible to spot. Our free JSON compare tool performs a structural diff and highlights every added key, removed key, and changed value in colour-coded output, drilling into nested objects and arrays to pinpoint the exact difference.

Key Features

Visual diff: Added (green), removed (red), and changed (yellow) keys highlighted at a glance
Deep nested comparison: Recursively diffs nested objects and arrays to the exact property level
Syntax validation: Flags invalid JSON before attempting a diff
Side-by-side view: Left and right panels for easy cross-reference
JSON Beautify: Format and prettify your JSON with one click
Browser-only: All processing is client-side, no server round-trip

How to Compare Two JSON Documents

Paste your first JSON document into the Left panel
Paste your second JSON document into the Right panel
Click Compare — the diff appears immediately
Added keys are green, removed keys red, changed values yellow

Common Use Cases

API testing: Compare an expected API response against the actual response to spot regressions
Configuration management: Diff environment config files (dev vs staging vs prod)
Feature flags: Compare feature flag states between environments
Debugging: Find the exact field that changed between two versions of a serialised object
Code review: Quickly understand what a JSON-producing function changed in its output

JSON Data Compare vs JSON Schema Compare

JSON Data Compare diffs two actual JSON documents — their keys, values, and structure. Use it for API responses and config files. JSON Schema Compare diffs two JSON Schema definitions — the structural rules that describe what valid data should look like. Use schema compare for API contract evolution and OpenAPI definitions.

Frequently Asked Questions

What changes does the tool highlight?: Added keys (in the right document but not the left), removed keys (in the left but not the right), and changed values (same key, different value). Unchanged keys are shown without colour.
Does it handle deeply nested JSON?: Yes — the diff is recursive. It drills into nested objects and arrays to find the exact property that differs rather than marking the entire parent as changed.
What is the difference between data compare and schema compare?: Data compare diffs actual JSON values. Schema compare diffs JSON Schema definitions (structural rules). Use data compare for API payloads; use schema compare for API contracts.
Is my JSON data private?: Yes. All comparison runs in your browser — your JSON is never sent to any server.

Privacy & Security

Both JSON documents are compared entirely in your browser. No data is transmitted to our servers.