Is my data stored or sent anywhere?

No. All comparison runs entirely in your browser using JavaScript. Your data never leaves your device — nothing is sent to any server. This tool is 100% client-side and privacy-first.

What file types can I compare?

You can compare any plain text including source code, configuration files, JSON, YAML, XML, SQL, Markdown, and more. The tool supports semantic diffing for JSON that ignores key ordering.

Is there a file size limit?

There is no hard limit. The tool uses efficient diffing algorithms to handle large files smoothly. Files with tens of thousands of lines work well in modern browsers.

Diff Checker — Free Online Text & Code Compare Tool

How to Use the Diff Checker

Paste or upload your original text on the left and modified text on the right.
Click Compare (or press Ctrl+Enter) to see the differences.
Switch between Side by Side and Inline views.
Use JSON mode for semantic comparison that ignores key ordering.
Navigate changes with the Prev/Next buttons or keyboard shortcuts.

Features

Side-by-side view — See original and modified text with aligned line numbers and color-coded changes.
Inline view — Unified diff format with additions and deletions shown sequentially.
Word-level highlighting — Changed words within a line are highlighted individually for precise change tracking.
JSON semantic diff — Compares JSON structures regardless of key ordering or formatting differences.
File upload — Drag and drop or click to upload text files for comparison.
Ignore whitespace — Toggle to skip whitespace-only changes.
Ignore case — Toggle for case-insensitive comparison.
Copy unified diff — Export the diff in standard unified format.
Change navigation — Jump between changes with Prev/Next buttons.
100% client-side — Your data never leaves your browser. No server processing, no tracking.

Keyboard Shortcuts

Ctrl+Enter / Cmd+Enter — Run comparison
Alt+Up — Previous change
Alt+Down — Next change

Why Privacy Matters for Diff Tools

Many online diff checkers upload your text to their servers for processing. This means sensitive code, configuration files, or proprietary content could be stored, logged, or exposed. Our diff checker processes everything locally in your browser using JavaScript — no data is ever transmitted. This makes it safe for comparing credentials, API keys, environment files, and any other sensitive content.