How many documents can I merge?

Add as many document panels as you need with the Add document button; they merge left to right.

What's the difference between shallow and deep merge?

Shallow merge only combines top-level keys; deep merge recursively merges nested objects.

How are array conflicts handled?

Choose concat to combine, replace so the later document wins, or union to combine while removing duplicates.

JSON Merger

Merge two or more JSON documents with shallow/deep strategies.

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Object merge strategy

Array strategy

Document 1

Document 2

Merged result

{
  "name": "Grace",
  "skills": [
    "logic",
    "math"
  ],
  "meta": {
    "role": "admin",
    "active": true
  }
}

Conflicts (1)

name: "Ada" → "Grace"

About the JSON Merger

Combine multiple JSON documents using shallow or deep merge strategies, with configurable array handling (concat, replace, or union), and a report of every key conflict encountered.

Examples

Deep merge two objects

{"a":{"x":1}}
{"a":{"y":2}}

Output

{"a":{"x":1,"y":2}}

Related tools

JSON Compare

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Diff two JSON documents and list added, removed, and changed paths.

JSON Formatter

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Pretty-print and beautify JSON with custom indentation.

JSON Key Sorter

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Sort JSON object keys alphabetically, naturally, or by array field.

JSON Minifier

JSON

Compress JSON by removing whitespace and show bytes saved.

JSON Repair / Auto-fixer

JSON

Auto-fix broken JSON: quotes, trailing commas, comments, and more.

JSON String Escape

JSON

Escape special characters for use inside a JSON string.

Frequently asked questions

Version 1.0.0 · Updated 2026-08-10 · Runs entirely in your browser