Text Diff Checker

Compare two texts line by line

Free online text diff checker. Compare two texts line by line with color-coded display of additions, deletions, and modifications. Perfect for code review, document proofreading, and change tracking. Works entirely in your browser with no data transmission.

How to Use

Check text differences in 3 steps:

Step 1: Enter Text
Paste the original text on the left and the text to compare on the right
Step 2: Compare
Click the 'Compare' button to display the differences
Step 3: Review Differences
Additions (green), deletions (red), and modifications are color-coded for easy identification

All comparisons are performed in your browser. No data is sent to servers.

Text Diff Checker

Text 1 (Original)

Text 2 (Compare)

Use Cases

Text diff checker is useful in various scenarios:

1. Code Review and Version Control

Identify changes in program code. Review modifications before committing, or compare two versions to track feature additions and deletions.

2. Document Proofreading

Compare documents before and after editing. Review changes made by editors or compare multiple versions to choose the best expressions.

3. Configuration File Comparison

Compare configuration files (.env, config.json, .htaccess, etc.) before and after changes. Identify differences between production and development environments.

4. Translation Review

Compare original and translated text side by side. Detect omissions or mistranslations, or evaluate multiple translation candidates.

5. Data Integrity Check

Compare two datasets (CSV, JSON, log files). Detect data discrepancies or missing entries to improve data quality.

What is Text Diff Checking?

Text diff checking (Diff) is a technology for comparing two texts and extracting differences. It is widely used in software development and document management.

How Diff Algorithms Work

This tool compares texts line by line, classifying each line as 'added', 'deleted', 'modified', or 'unchanged'. Added lines are shown in green, deleted lines in red, and modified lines in both red and green. Line numbers are displayed for precise location identification.

Why Diff Checking Matters

In software development, version control systems like Git use diff to track code changes. In document management, it's used for reviewing edit history and merging changes from multiple authors. Visualizing differences helps quickly understand the scope of changes.

Safe Browser-Based Processing

This tool uses JavaScript to perform diff calculations entirely in your browser. Since text is not sent to servers, you can safely compare code or documents containing confidential information. It works offline, so you can use it even without an internet connection.

Frequently Asked Questions

Is there a limit to the text length I can compare?

As long as your browser has sufficient memory, you can compare long texts. Typically, texts with thousands of lines work fine. However, very large files (tens of thousands of lines or more) may slow down browser performance.

What do the colors mean?

Green lines indicate 'additions', red lines indicate 'deletions', and lines showing both red and green indicate 'modifications'. Gray lines are identical in both texts. This color coding allows you to grasp changes at a glance.

Does it support syntax highlighting for programming code?

Currently, syntax highlighting is not supported. This tool specializes in text diff display and is designed as a general-purpose comparison tool independent of programming languages. You can compare any type of text: code, documents, configuration files, etc.

Are differences in whitespace and tabs detected?

Yes, all characters including spaces, tabs, and line breaks are compared. Different numbers of spaces or mixed tabs and spaces are detected as 'modifications'. This allows you to accurately check indentation differences in code.

Can I save the comparison results?

Currently, there is no direct save feature for comparison results. However, you can save results using your browser's screenshot or print functions. Results are retained as long as you don't refresh the page after displaying the diff.

What's the difference from Git's diff command?

Git's diff uses multiple algorithms (Myers, Patience, etc.) for more advanced diff calculations. This tool provides simple line-by-line comparison and has the advantage of working without Git. It runs in any web browser, so you can use it immediately without environment setup.

Can I compare only part of a text?

Yes, you can copy and paste only the parts you want to compare. There's no need to compare entire files. You can efficiently check differences by extracting and comparing specific functions, paragraphs, or configuration items.

Are uppercase and lowercase letters distinguished?

Yes, uppercase and lowercase are treated as different characters. For example, 'Hello' and 'hello' are detected as different lines. This allows you to accurately detect differences in variable names in code or uppercase/lowercase in SQL statements.