Text Compare
Compare two text documents or code snippets side by side to find differences instantly. This diff tool highlights additions, deletions, and modifications with clear color-coded markers, making it easy to spot what changed between versions. Ideal for developers reviewing code changes, writers proofreading revisions, or anyone who needs to verify document edits. The entire comparison runs locally in your browser, ensuring your sensitive text never leaves your device.
What is Text Comparison?
Text comparison (or diff checking) is the process of identifying differences between two pieces of text. The tool takes an original version and a modified version, then highlights exactly what was added, removed, or changed. Differences are displayed with clear color coding — typically green for additions, red for deletions, and yellow for modifications — making it immediately obvious what changed between versions.
Text comparison is fundamental to version control, code review, document editing, and content management. It automates the tedious and error-prone process of manually reading two documents side by side to spot differences. Even for short texts, human diff detection is unreliable; for long documents, it is practically impossible without tool assistance.
When Should You Compare Text?
Text comparison is essential for code review, where developers need to see exactly what changed between commits. Writers use diff tools to review edits and track changes across drafts. Legal professionals compare contract versions to identify modified clauses. Configuration file changes need verification before deployment. Data analysts compare dataset exports to identify changes.
Developers using version control systems compare file versions to understand changes. Technical writers compare document revisions to verify edits. QA engineers compare expected vs actual output to identify bugs. Anyone who needs to understand what changed between two text versions benefits from comparison tools.
How It Works
The tool uses the Longest Common Subsequence (LCS) algorithm to find the maximum shared content between the two texts. Differences are identified as segments that are not part of the LCS — insertions (present only in the new text), deletions (present only in the old text), and modifications (different content at the same position). The results are displayed side-by-side with color-coded highlighting.
Tips for Best Results
For the clearest results, compare files of similar content type — do not compare a JavaScript file against a CSS file. Normalize line endings (CRLF vs LF) before comparing to avoid false positives. For large files, focus comparison on specific sections rather than entire documents. Use the line numbers in the output to quickly navigate to specific changes.
Features
How to Use
Paste the original text into the left panel
Paste the modified text into the right panel
Click 'Compare' to highlight all differences between the two
Review the color-coded additions and deletions, then copy the results
Frequently Asked Questions
What is a diff checker?
Can I compare code?
Does it show line numbers?
Is my data sent to a server?
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