JSON Compare

Compare JSON files side-by-side to find differences instantly.

Added (Right)
Deleted (Left)
Modified
Compare JSON Format Both Load Sample Clear

About JSON Compare

JSON Compare is a free online tool designed for developers, data analysts, and system administrators to visualize differences between two JSON files. Debugging changes in large data structures can be difficult; missing a single key or value change in a 5,000-line file is easy to do. This tool highlights those changes instantly.

Key Features

  • Side-by-Side View: View both the original and modified JSON simultaneously to easily spot structural changes.
  • Syntax Highlighting: The editor color-codes your JSON, making keys, values, and arrays easy to read.
  • Auto-Formatting: Automatically pretty-prints your JSON before comparison to ensuring that whitespace issues don't trigger false positives.
  • Error Detection: Validates your JSON before comparing, letting you know exactly where a syntax error occurred.

How to Use

  • Paste Data: Enter your original JSON in the left panel and the new/modified version in the right panel.
  • Compare: Click the "Compare JSON" button. The tool will align the code and apply background colors to changed lines.
  • Review:
    • Green lines indicate data added to the new file.
    • Red lines indicate data removed from the original.
    • Yellow lines indicate values that have been modified.

Frequently Asked Questions

Does the order of keys matter?

In standard JSON objects, key order does not matter. However, for visual comparison, our tool attempts to align keys. If keys are in a significantly different order, they may show as changes. We recommend using the "Format Both" button, which helps standardize the structure.

Is my data secure?

Yes. This tool runs entirely in your web browser (client-side). Your JSON data is processed locally via JavaScript and is never sent to our servers.

Can I compare minified JSON?

Yes. The tool automatically "pretty prints" (expands) minified JSON into a readable, indented format before running the comparison, so you don't need to format it manually.

Is there a file size limit?

Because the processing happens in your browser, the limit depends on your computer's memory (RAM). Generally, files up to several megabytes (10,000+ lines) work smoothly, but extremely large datasets may slow down the browser.

Can I merge the files?

Currently, this is a viewer tool designed to identify differences. It does not support merging or saving the combined output. It is best used for debugging and verification.