Advanced Code Compare
A developer-grade diff checker. Upload files or paste code to instantly highlight differences, ignore whitespace, and export reports.
Advanced Diff Checker Features
Drag & Drop Upload
Instantly load `.txt`, `.html`, `.js`, `.json` and more by simply dragging files into the editor blocks.
Dynamic View Modes
Toggle between Side-by-Side (Split) view for standard comparisons, or Line-by-Line (Unified) for a Git-style diff.
Syntax Highlighting
Our engine automatically detects programming languages and applies rich syntax highlighting to the diff results.
Shareable URLs
Generate a unique, compressed URL containing your code comparison to easily share bugs or changes with teammates.
Where Can You Use This Diff Tool?
Software Development
Compare local code changes before committing to Git. Spot missing semicolons or accidental deletions instantly.
Legal & Copywriting
Compare two versions of a contract, terms of service, or blog post to see exactly what vocabulary was altered.
Data & JSON Checking
Paste two massive JSON payloads or CSV dumps to visually locate missing data nodes or modified values.
Why Use Toolszu Code Compare?
We engineered the most powerful, privacy-first diff checking suite available online.
- 100% Client-Side Privacy: Your proprietary source code and sensitive documents never leave your computer. Processing happens entirely within your web browser.
- Word-Level Highlighting: Unlike basic tools that only highlight whole lines, our engine pinpoints the exact character or word that changed within a modified line.
- Smart Ignore Features: Stop stressing over code formatting. Toggle "Ignore Whitespace" to only see logical code changes rather than indentation differences.
- Professional Exports: Need to document the changes? Instantly export the visual diff as a polished PDF report or standalone HTML file for your records.
Frequently Asked Questions
An online code compare (or "diff checker") tool takes two blocks of text, analyzes them simultaneously, and visually highlights the exact differences. The left side usually shows the original file with deletions marked in red, while the right side shows the new file with additions marked in green.
You can either click the "Upload" button located at the top of both input boxes, or you can simply drag and drop your files directly from your computer into the editor areas. The tool will instantly read the file and preserve all your formatting.
When formatting code, developers often change tabs, spaces, or line breaks without changing the actual logic. By checking "Ignore Whitespace", the diff engine will ignore these superficial layout changes and only highlight actual alterations to text, variables, or syntax.
Yes, completely secure. The comparison algorithms (`jsdiff`) run entirely on the client-side within your browser. Your pasted text or uploaded files are never uploaded, transmitted, or saved to our servers.
When you click "Share Link", the tool compresses both the original and changed text directly into the URL using LZ-String encoding. Because no database is used, the link might be long, but it allows you to instantly share the exact comparison state with colleagues without relying on external servers.