Comparing two versions of a text by eye is unreliable — a changed date, a deleted clause, or a swapped word is easy to miss. Diff tools solve this by aligning two texts and highlighting exactly what was added, removed, or modified. Programmers use diffs every day in code review, but the technique is just as valuable for contracts, articles, translations, and configuration files.
This checker compares two blocks of text line by line and highlights insertions in green and deletions in red, so every difference is visible at a glance. Both texts stay in your browser; nothing is uploaded.
How to Use This Tool
- Paste the original text into the left box.
- Paste the modified version into the right box.
- Click compare to see a highlighted, line-by-line difference view.
- Review green lines (added) and red lines (removed) to audit every change.
Frequently Asked Questions
How does the comparison work?
The tool uses a line-based longest-common-subsequence algorithm, the same family of algorithms behind git diff. It finds the largest unchanged blocks and marks everything else as added or removed.
Can I compare code with it?
Yes. Line-based diffing is exactly how developers compare source code. Paste two versions of a file to see what changed between them — useful when you do not have git at hand.
Is there a size limit?
There is no hard limit, but extremely large texts (hundreds of thousands of lines) may be slow because the comparison runs in your browser. For typical documents and source files it is instant.