TOOLOG TOOL

JSON Merge | Combine Multiple JSON Files at Once

Upload multiple JSON files and merge them into a single downloadable JSON output in your browser.

Data/Utility

Merge mode Auto (recommended) Concatenate arrays Merge object keys (later files win) Auto-concatenate common array in objects Wrap file roots into array

Remove duplicates when merging arrays

0Uploaded files

-Merged item count

-Duplicate keys (object mode)

-Output size (bytes)

Upload multiple JSON files with similar format and merge/download them at once.

Download merged.json

When should you use JSON Merge?

Use it when split JSON files with similar schema need to be combined quickly.

Examples: paged API exports, chunked logs, and batch output files.

Key features

• Multi-file JSON upload
• Auto mode detects array/object structure
• Manual modes: array concat, object key merge, wrap roots into array
• Preview + merged.json download

How to use

1. Upload multiple JSON files.
2. Pick a merge mode (default: Auto).
3. Click Merge JSON.
4. Review and download the result.

Notes

• In object-merge mode, duplicate keys are overwritten by later files.
• Very large files can increase browser memory usage.

Related tools

• Text length check: Text Counter
• Key/style cleanup: Case Converter

Related tools

Text Counter Count characters with and without spaces, words, and UTF-8 bytes in one view. Case Converter Instantly convert text between UPPERCASE, lowercase, Title Case, camelCase, and snake_case.