Code Diff Checker - Compare Two Files Side by Side Free

Last Updated: April 1, 2026

Last updated: 2026-03-15

You have two versions of a file and need to see what changed. Maybe you are reviewing a pull request without GitHub, comparing config files between environments, or checking what a colleague modified. A diff tool highlights every addition, deletion, and modification.

Diff View Modes

Mode	Layout	Best For
Side by side	Old on left, new on right	Comparing two complete files
Inline (unified)	Single column, changes highlighted	Reading changes sequentially
Character-level	Highlights individual character changes within lines	Finding subtle changes (typos, variable renames)

Features

Syntax highlighting. Supports 50+ programming languages.
Ignore whitespace. Option to ignore spaces, tabs, and line endings.
Ignore case. Option for case-insensitive comparison.
Line numbers. Both original and modified line numbers shown.
Jump to next change. Navigate between differences quickly.

Common Use Cases

Code review. Compare before and after versions of code.
Config comparison. Find differences between staging and production configs.
Document comparison. Compare two versions of a document or contract.
Debug. Compare working and broken versions to find the bug.

Compare two files - syntax highlighted, free, instant.

Open Diff Checker →

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According to Git documentation, the unified diff format is the standard for representing file differences.

As MDN Web Docs explains, the File API enables browser-based file reading for client-side diff comparison.

Frequently Asked Questions

Is this coding tool free?

Yes, all developer tools on TXT1.com are free to use without registration.

What programming languages are supported?

We support JSON, XML, HTML, CSS, JavaScript, SQL, Base64, and many more formats.

Is my code secure?

All code is processed locally in your browser when possible, ensuring maximum privacy.

Can I use this for production code?

Yes, our tools are used by thousands of developers for real-world projects every day.

Do you offer an API?

API access is available for high-volume users. Contact us for details.

14.1K

Happy Users

54.1K

Files Processed

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User Rating

💡 Pro Tip: Drag and drop files directly onto the tool for instant processing. Works with multiple files too!

Supported Formats

TXT MD HTML RTF DOCX PDF

🔗 Frequently Used With

Tool Categories SQL Formatter & Beautifier HTML to Markdown Converter - Free Online Tool

Why Choose This Tool

🔒 100% Private

Files processed in your browser. Nothing uploaded.

⚡ Lightning Fast

AI-powered processing in seconds, not minutes.

💰 Always Free

No hidden fees, no signup, no limits.

🌐 Works Everywhere

Any device, any browser. No installation needed.

How It Works

Upload

Drop your file or paste content into the input area

Process

Click the button and let AI do the heavy lifting

Download

Get your result instantly, ready to use

User Reviews

Emily R.★★★★★

"Super easy to use, no signup required. Perfect for quick tasks between classes."

Student

Alex T.★★★★★

"Replaced a paid subscription with this free tool. Couldn't be happier."

Small Business Owner

Maria G.★★★★★

"Finally a tool that just works without asking for my email first."

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