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JSON Diff Tutorial

Complete guide to comparing JSON and detecting changes

What is JSON Diff?

JSON Diff (JSON Difference/Comparison) is a technique to compare two JSON documents and identify differences. Unlike simple text comparison, JSON Diff understands JSON structure and semantics, detecting meaningful changes like field additions, removals, type changes, and value modifications. Our tool automatically categorizes changes by impact level (Breaking/Risky/Safe) to help you quickly assess API compatibility.

Why Use JSON Diff?

  • API Version Comparison: Quickly identify breaking changes between old and new API versions
  • Frontend-Backend Integration: Verify API response compatibility before deployment
  • Regression Testing: Ensure new code changes don't break existing API contracts
  • Documentation: Generate clear change reports for team communication
  • Schema Validation: Automatically infer and compare JSON schemas

How to Use JSON Diff Tool

Step 1: Prepare Your JSON

Copy the original JSON response from your API or file. Ensure it's valid JSON format. You can use our built-in JSON validator to check.

Step 2: Paste Both Versions

Paste the old JSON in the left panel and the new JSON in the right panel. Our tool supports formatted, minified, or raw JSON input.

Step 3: Click Compare

Click the "Compare" button. Our engine will automatically analyze both JSON documents, infer schemas, and detect all differences.

Step 4: Review Results

Review the categorized results: Breaking Changes (red), Risky Changes (yellow), and Safe Changes (green). Download the report or share with your team.

Understanding Diff Results

🔴 Breaking

Breaking Changes: Field removals, incompatible type changes (e.g., string→number), required field becoming nullable. These changes will likely break existing clients and require immediate attention.

🟡 Risky

Risky Changes: Nullability changes (non-null→nullable or vice versa), array structure changes, enum value changes. These changes might break some clients depending on their implementation.

🟢 Safe

Safe Changes: New field additions, new enum values, description changes. These changes are generally backward compatible and safe to deploy.

Common Use Cases

API Version Migration

Compare v1 and v2 API responses to create migration guides and identify breaking changes for clients.

CI/CD Integration

Integrate JSON Diff into your pipeline to automatically detect breaking changes before deployment.

Contract Testing

Verify that backend changes maintain contract compatibility with frontend applications.

Code Review

Generate clear diff reports to help reviewers understand API changes in pull requests.

Pro Tips

  • Use the Git Diff view for line-by-line comparison of large JSON files
  • Download reports for documentation and team collaboration
  • All processing happens in your browser - your data never leaves your machine
  • Bookmark specific diff results by saving both JSON inputs locally

Ready to compare your JSON?

Try JSON Diff Tool Now
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