Free Online JSON Diff & Compare Tool

Compare two JSON objects side by side. See added, removed, and changed values highlighted.

What is JSON Comparison?

JSON comparison (or "diff") is the process of identifying differences between two JSON objects. This is essential for:

• API Versioning: Detect breaking changes between API response versions
• Configuration Drift: Compare current config with expected baseline to identify unintended changes
• Test Assertions: Verify that API responses match expected values in automated tests
• Data Migration: Identify what has changed before and after data transformations
• Audit Trails: Track modifications to critical JSON documents over time

Features

How It Works

The comparison algorithm uses recursive deep comparison to examine both JSON objects:

1. Parse: Both JSON strings are parsed into JavaScript objects (with support for lenient syntax)
2. Traverse: The algorithm recursively walks through both object trees simultaneously
3. Categorize: Each difference is categorized as added (exists only in right), removed (exists only in left), or changed (different values)
4. Track Path: The full path to each difference is recorded (e.g., config.theme or features[3])
5. Display: Results are presented in a table with color coding and truncated value previews

The algorithm handles:

• Primitive values (strings, numbers, booleans)
• Nested objects and arrays
• Type mismatches (e.g., string vs. number)
• Null and undefined values
• Array length differences