Free JSON Merge Tool - Combine JSON Files
Merge multiple JSON objects into one document online. Choose from deep merge, shallow merge, or concatenation strategies. Combine JSON files instantly for free.
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What is JSON Merge?
JSON Merge is a free online tool that combines multiple JSON objects into a single unified document. It supports different merge strategies: deep merge (recursively combines nested objects), shallow merge (overwrites top-level keys), and concatenation (creates an array of all inputs).
How to Use JSON Merge
- Paste your first JSON document in the left panel
- Paste additional JSON documents (click 'Add JSON' for more inputs)
- Select your preferred merge strategy
- Click 'Merge' and copy the combined result
JSON Merge Features
- Deep merge with recursive object combination
- Shallow merge for simple key overwriting
- Concatenation to create arrays from multiple documents
- Option to concatenate or replace arrays during deep merge
- Support for merging 2+ JSON documents at once
JSON Merge FAQ
What's the difference between deep and shallow merge?
Shallow merge only combines top-level keys - if both objects have the same key, the second value overwrites the first. Deep merge recursively combines nested objects, preserving properties from both sources.
How are arrays handled?
With 'Concatenate arrays' enabled, arrays at the same path are combined. With it disabled, the array from the later document replaces the earlier one.
Can I merge more than 2 JSON documents?
Yes! Click 'Add JSON' to add more input panels. All documents are merged in order from left to right, top to bottom.