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Data Processing
· Last updated：2025-09-30
Merge multiple JSON files with various merging strategies (deep merge, overwrite, combine arrays, etc.)
Execution
Fill in the form, run the tool, and review the result in one place.
Samples
Related
Tool usage guide
The JSON File Merger is a powerful utility designed to combine multiple JSON files into a single, unified document using customizable merging strategies, including deep recursive merging, array concatenation, and conflict resolution.
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Best for
Not ideal for
Trailing commas or single quotes
Strict JSON parsers reject them — remove trailing commas and switch to double quotes before validating or formatting.
Very large files
Large files take longer and can hit browser memory limits — try a smaller sample first.
Skipping the output check
Compare the first rows or pages of the output with the input before using it in production.
Background
A developer has separate JSON files for database settings, API keys, and UI themes.
Problem
Need to combine these into one 'config.json' without losing nested structure.
How to use
Upload all config files, select 'Deep Merge' strategy, and choose 'Prettified' output.
Outcome
A single, clean JSON file containing all configuration parameters merged into their respective nested objects.
Background
Multiple translators submitted JSON files for different sections of a website.
Problem
Need to merge these into one master translation file while ensuring no keys are lost.
How to use
Upload all translation files, select 'Deep Merge', and 'Concatenate' for any array-based lists.
Outcome
A unified translation file ready for deployment, with all keys and array values correctly aggregated.
A deep merge recursively combines nested objects, while a shallow merge only combines top-level properties, with later files overwriting earlier ones.
Yes, you can select 'Concatenate' or 'Merge Unique' in the Array Handling settings to combine array contents rather than overwriting them.
You can define the behavior in the Conflict Resolution settings, choosing to overwrite with the last value, keep the first value, or stop the process with an error.
You can upload up to 5 files at a time, with a total file size limit of 10MB.
Yes, the Output Format option allows you to choose between standard, compact, or prettified JSON with 4-space indentation.