Text Diff
Compare two texts and highlight every difference. Switch between character, word, and line-level comparison with side-by-side or unified view — all processed locally.
🔒 Your texts never leave your device — all comparison is done locally
100% secure
Your files are never shared
Ultra-fast
Processing in seconds
Privacy
Automatic deletion after 1h
How to Compare Two Texts
Paste your texts
Paste the original text in the left panel and the modified text in the right panel. You can also load .txt, .json, .csv or any other text file.
Choose your options
Select the comparison level (characters, words or lines) and the view (side by side or unified). Enable options to ignore case or whitespace if needed.
Analyze the differences
Additions appear in green, deletions in red. Navigate between differences and copy or download the result.
Text Diff Use Cases
| Use case | Recommended level | Recommended view |
|---|---|---|
| Compare two versions of an article | Words | Side by side |
| Code review (source code) | Lines | Side by side |
| Find a typo | Characters | Unified |
| Compare configuration files | Lines | Side by side |
| Check contract modifications | Words | Side by side |
| Compare API JSON responses | Lines | Unified |
What is a Text Diff?
A text diff (short for "difference") is the result of comparing two pieces of text to find what has changed between them. The comparison algorithm identifies additions, deletions, and unchanged sections.
This tool uses the Myers diff algorithm — the same algorithm used by Git and other version control systems. It finds the minimum set of changes needed to transform one text into another, producing clean and readable results.
Text diff is essential for code review, document version tracking, contract comparison, plagiarism detection, and any scenario where you need to understand what changed between two versions of a text.
Character, Word, and Line Comparison
Character-level comparison shows every single character that was added or removed. This is the most precise mode, ideal for finding typos or subtle changes. Word-level comparison groups changes by word, which is more readable for natural text like articles or emails.
Line-level comparison treats each line as a unit. This is the standard mode for source code and configuration files, matching how Git and other developer tools work. Choose the level that best fits your content.
Privacy & Security
This text comparison tool runs entirely in your web browser. No text is ever sent to a server, stored in a database, or shared with third parties. You can safely compare confidential documents, source code, or any sensitive content.
Text Diff — Frequently asked questions
How do I compare two texts online?
Paste the original text in the left panel and the modified text in the right panel. The differences are highlighted automatically: additions in green, deletions in red. You can also load text files directly.
What is the difference between side-by-side and unified view?
Side-by-side view shows both texts in two aligned columns, like GitHub. Unified view shows everything in a single column with + and - markers, like git diff. Side-by-side is better for detailed review, unified is more compact.
Is my data sent to a server?
No. All text comparison is performed entirely in your browser using JavaScript. Your texts are never uploaded, stored, or transmitted to any server. Your data stays 100% private.
Can I compare source code?
Yes! The line-level comparison mode is ideal for code review. You can load .js, .py, .json, .css, .html, and many other file formats directly. The monospace font and line numbers make code easy to read.
How do I compare two text files?
Click "Load file" below each text panel to upload files. The tool accepts .txt, .json, .csv, .xml, .html, .css, .js, .md, .py, and more. File contents are loaded locally and compared instantly.
Does the tool support large files?
The tool handles files of several thousand lines efficiently. For very large files (10,000+ lines), line-level comparison is recommended as it is faster than character or word-level comparison.
How do I ignore whitespace or case differences?
Use the checkboxes in the options bar: "Ignore case" converts both texts to lowercase before comparing, "Trim whitespace" removes leading/trailing spaces from each line, and "Ignore empty lines" filters out blank lines.
What is a .diff file?
A .diff file is a standard text format that records differences between two files using + and - markers. It is used by version control systems like Git. You can download your comparison result in this format.