Deep merge two JSON objects

Combine two JSON values with recursive object merging and a chosen array strategy.

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ToolJSON Merge
Input
Output
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Preview

How it works

Both values are parsed, plain objects merge recursively, scalar conflicts use the later value, and arrays replace, concatenate, or concatenate uniquely according to the selected strategy. The result is serialized with indentation.

  • Array replacement is the least-assumptive default.
  • Alternative list strategies are explicit because arrays have no universal identity key.

Worked example

Deep Merge Objects
Deep merge two configuration objects, combining nested properties
Input
											{"database": {"host": "localhost", "port": 5432}, "logging": {"level": "info"}}
Output
												{
  "database": {
    "host": "localhost",
    "port": 5432
  },
  "logging": {
    "level": "info"
  }
}

When to use this

Configuration overlays, deployment defaults, and scenario fixtures combine JSON objects.

Edge cases

  • A scalar replacing an object discards the earlier branch.
  • Concatenation preserves duplicates unless unique mode is selected.
  • Different nested types use the later branch.

References