Text Diff

What is a Text Diff?

A text diff is a comparison between two blocks of text that highlights the differences between them. The term "diff" comes from the Unix utility of the same name, which has been used by developers for decades to compare file versions. Our text diff tool brings this capability to your browser, making it accessible to everyone, not just programmers.

The diff algorithm works by finding the longest common subsequence (LCS) between the two texts and then marking lines that exist only in the original text as removed (shown in red) and lines that exist only in the modified text as added (shown in green). Lines that are identical in both texts are left unstyled. This makes it easy to see exactly what changed between two versions at a glance.

Text diff tools are fundamental to version control systems like Git, collaborative editing workflows, and code review processes. They are also useful for non-technical purposes such as comparing contract revisions, tracking changes in documents, or verifying that edits were applied correctly.

How to Use This Tool

Using the text diff tool is simple. Paste your original text into the left panel and your modified text into the right panel. Click the "Compare" button to generate the diff. The result shows each line with a visual indicator: lines starting with a plus sign (+) and green background are additions, lines starting with a minus sign (-) and red background are removals, and unchanged lines have no special styling.

The tool also displays summary statistics showing the total number of additions and deletions. This gives you a quick overview of how much the text has changed. Click "Clear" to reset both text areas and the diff output.

Common Use Cases

Comparing Document Revisions

When collaborating on documents, it is common to receive revised versions. A text diff lets you quickly see what the other person changed without manually reading through the entire document. This is useful for contracts, reports, proposals, and any collaborative writing project.

Code Review

Developers use diff tools daily to review code changes. Before merging a pull request, reviewing the diff ensures that unintended changes are caught and that the code quality is maintained. Our browser-based tool is perfect for quick reviews without needing to install anything.

Content Editing

Editors and content creators can use text diff to compare drafts, verify corrections made by proofreaders, or track the evolution of an article through multiple revision cycles. It provides an objective record of every change made.

Frequently Asked Questions

How does the diff algorithm work?

Our tool uses the Longest Common Subsequence (LCS) algorithm to find the optimal alignment between the two texts. It compares the texts line by line and identifies which lines are shared and which are unique to each version. The result is a unified diff view that shows additions and removals clearly.

Can I compare texts with different line endings?

Yes. The tool normalizes line endings during comparison, so texts with different line ending styles (LF vs CRLF) will still be compared correctly based on their content.

Is there a size limit for the texts?

The tool runs entirely in your browser, so the practical limit depends on your device's memory and processing power. For most use cases, texts up to a few thousand lines work well. Very large texts (tens of thousands of lines) may take longer to process.

Is my text stored anywhere?

No. All processing happens locally in your browser. Your text is never sent to any server or stored anywhere. You can safely compare sensitive documents without privacy concerns.