JSON Merge is a free, client-side web tool for merging, comparing, splitting, editing, and visualizing JSON data, running entirely in the browser without requiring login or server storage.
What is JSON Merge?
JSON Merge is an online utility that takes two JSON inputs (via paste or file upload) and produces a single merged JSON output. It runs in the browser using client-side processing — no data is sent to a server or stored after use. The tool is built and maintained by JSON Merge (no company name specified on the page), and is available at jsonmerge.com.
Key Features
- Smart merging — Handles nested structures, arrays, and complex objects while preserving data integrity.
- Instant processing — Merges JSON files in the browser without waiting for server round-trips.
- Customizable conflict resolution — Offers multiple algorithms to decide how conflicting keys should be combined.
- Visual side-by-side diff — Compare two JSON files with an intuitive visual diff tool before merging.
- Upload or paste input — Accepts JSON data typed directly or uploaded as files (no file size limit stated, but large files are supported).
- Download or copy output — Merged result can be downloaded as a file or copied to clipboard.
- No login, no cost — 100% free, no account required, no hidden fees.
Who is it for?
- Developers — Quickly merge API responses, configuration files, or database exports without writing merge logic.
- Data analysts — Combine JSON datasets from different sources before processing or cleaning.
- IT professionals — Validate and merge JSON schemas or configuration files across environments.
What can you do with JSON Merge?
- Merge two API responses — Combine JSON data from two endpoints (e.g., user profiles and order history) into a single object for debugging or testing.
- Compare and merge configuration files — Use the visual diff tool to see differences between two settings files, then apply the merge.
- Merge nested objects — Combine deeply nested JSON structures (e.g., complex app state objects) with conflict resolution that respects nested key hierarchies.
How does it work?
- Paste or upload your first JSON into the JSON 1 area.
- Paste or upload your second JSON into the JSON 2 area.
- Click Merge and customize merge settings (conflict resolution algorithm) if needed.
- Download or copy the merged result.
Pricing
JSON Merge is 100% free to use. No login, no subscription, no payment required.
FAQ
Is JSON Merge free?
Yes, all features — merging, comparing, validating, and visualizing — are completely free with no usage limits.
Does JSON Merge store my data?
No. All processing happens client-side in your browser. Your JSON data never leaves your device and is not stored on any server.
What conflict resolution algorithms are available?
The tool provides multiple configurable algorithms for handling key conflicts between the two JSON inputs (detailed on the merge settings panel). The exact algorithm names are not listed on the page, but users can customize behavior before merging.
Can JSON Merge handle large files?
Yes, the service is optimized to process large JSON files efficiently, though no specific file size limit is stated.
Do I need to create an account?
No registration or login is required to use any tool on jsonmerge.com.
