Free Developer Utility
JSON Merge Tool
Merge two or more JSON documents online with predictable merge modes, live validation, beautified or minified output, copy actions, and clean downloadable JSON.
JSON Merge Workspace
Input 1
Waiting for validation
Input 2
Waiting for validation
Merged Output
JSON Merge Guide
Merge JSON Files Online
Use this JSON merge tool to combine configuration files, package data, translation files, schema fragments, exported settings, and nested JSON objects. Paste two or more JSON documents, choose a merge mode, and export a clean merged JSON file.
When to use it
- Combine multiple JSON configuration files into one final file.
- Merge JSON response samples while preserving nested object structure.
- Compare overwrite, append, and deep merge behavior before using JSON in an app.
Merge modes
- Overwrite replaces matching keys with values from later inputs.
- Append keeps repeated values together where possible.
- Deep Merge combines nested objects and appends arrays.
JSON Merge Tool FAQ
What does a JSON merge tool do?
A JSON merge tool combines two or more valid JSON inputs into one output. It is useful for joining settings, nested objects, arrays, examples, and structured data files.
What is the difference between overwrite and deep merge?
Overwrite replaces matching top-level keys with values from later inputs. Deep merge walks into nested objects, combines matching object keys, and appends arrays.
Can I merge more than two JSON files?
Yes. Add more input panels or upload multiple JSON files, then merge them in order from top to bottom.
Does the tool validate JSON before merging?
Yes. The tool checks each input and shows validation errors before producing merged output.