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JSON Merge Tool

Combine multiple JSON files with advanced merge strategies. Perfect for configuration files, data consolidation, and API response merging.

Merge Configuration
Choose your merge strategy and configure options
JSON 1
JSON 2
Merged Result
The combined JSON output from all your input files
JSON Editor
Ln 1, Col 10 lines0 characters0 B
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How to Use JSON Merge Tool
Follow these simple steps to merge your JSON files effectively
1

Add JSON Data

Paste JSON content or upload files

2

Choose Strategy

Select your preferred merge method

3

Merge Files

Click merge to combine your JSON

4

Download Result

Copy or download the merged JSON

Merge Strategies Explained
Understanding different merge approaches for your JSON data

Deep Merge (Recommended)

Recursively merges nested objects and arrays. When the same key exists in multiple objects, it combines the values intelligently rather than overwriting them.

Best for:

  • Configuration files with nested settings
  • User profiles with multiple data sections
  • API responses that need to be combined

Shallow Merge

Only merges the top-level properties. If the same key exists in multiple objects, the last value overwrites previous ones.

Best for:

  • Simple flat JSON objects
  • When you want later values to override earlier ones
  • Performance-critical applications

Array Concatenation

When merging arrays, concatenates them together instead of replacing. Objects are still deep merged.

Best for:

  • Combining lists of items
  • Merging multiple data collections
  • Preserving all array elements

Array Replacement

When merging arrays, the later array completely replaces the earlier one. Objects are still deep merged.

Best for:

  • When you want to override entire arrays
  • Configuration updates
  • Data replacement scenarios

What is JSON Merge?

JSON merge is the process of combining multiple JSON (JavaScript Object Notation) files or objects into a single, unified JSON structure. This powerful technique is essential for developers working with configuration files, API responses, user data, and complex data structures that need to be consolidated from multiple sources.

Our advanced JSON merge tool supports multiple merge strategies, allowing you to choose the best approach for your specific use case. Whether you need to combine configuration files, merge user profiles, or consolidate API responses, our tool provides the flexibility and power you need.

Common JSON Merge Use Cases

Configuration Files

Merge environment-specific config files with base configurations for deployment automation.

API Responses

Combine data from multiple API endpoints to create comprehensive data objects.

User Profiles

Merge user data from different sources like social profiles, preferences, and settings.

Data Migration

Consolidate data from legacy systems during database migrations and updates.

Testing Data

Combine test fixtures and mock data for comprehensive testing scenarios.

Localization

Merge translation files and locale-specific data for internationalization.

JSON Merge Best Practices

1. Choose the Right Merge Strategy

Select deep merge for nested objects, shallow merge for simple structures, and consider array handling based on your data requirements.

2. Validate Input Data

Always validate your JSON files before merging to avoid errors and ensure data integrity throughout the merge process.

3. Handle Conflicts Carefully

Plan how to handle conflicting keys and values. Document your merge strategy for team consistency and future maintenance.

4. Test with Sample Data

Use our example data feature to test your merge strategy before processing production files. Verify the output matches your expectations.

5. Consider Performance

For large files, shallow merge is faster than deep merge. Consider breaking large files into smaller chunks for better performance.

JSON Merge Tips & Tricks

Performance Tips

  • • Use shallow merge for large, flat objects
  • • Deep merge is best for nested configurations
  • • Consider array strategy based on data type
  • • Validate JSON before merging to avoid errors

Advanced Techniques

  • • Use example data to test merge strategies
  • • Plan conflict resolution before merging
  • • Document your merge approach for teams
  • • Backup original files before merging
Ready to Get Started?

Choose from our suite of JSON tools to start processing your data right away.

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JSON to CSV

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JSON to Excel

Transform JSON into Excel spreadsheets with automatic column detection.

Frequently Asked Questions
What is a JSON merge tool?

A JSON merge tool is a utility that combines multiple JSON files or objects into a single JSON structure. It handles conflicts between duplicate keys and provides various strategies for merging nested objects and arrays.

What are the different JSON merge strategies?

Common JSON merge strategies include: Deep Merge (recursively combines nested objects), Shallow Merge (only merges top-level properties), Array Concatenation (combines arrays), and Array Replacement (replaces arrays entirely).

How do I merge JSON files with conflicting keys?

When merging JSON files with conflicting keys, the merge strategy determines the outcome. Deep merge combines nested objects, while shallow merge uses the last value. Choose the strategy that best fits your use case.

Can I merge more than two JSON files?

Yes, you can merge multiple JSON files simultaneously. The tool processes them sequentially, applying your chosen merge strategy to combine all files into a single result.

Is JSON merging secure and private?

Yes, our JSON merge tool processes everything client-side in your browser. No data is uploaded to servers, ensuring complete privacy and security of your JSON files.

What file formats are supported for JSON merging?

The tool supports .json files and direct JSON text input. You can upload files or paste JSON content directly into the text areas for merging.

How do I handle large JSON files when merging?

For large JSON files, use deep merge strategy carefully as it requires more processing. Consider shallow merge for better performance with large datasets, and ensure your browser has sufficient memory.

Can I download the merged JSON result?

Yes, after merging your JSON files, you can download the result as a .json file or copy it to your clipboard for use in other applications.