Diff Checker
Compare two texts side by side
How to use Diff Checker
- Paste your original text into the left panel and the modified version into the right.
- The diff is computed automatically and shown below.
- Choose side-by-side or unified view.
- Use the ignore options to skip whitespace, case, or trailing spaces differences.
What is a text diff?
A diff (short for difference) is a comparison between two versions of text that highlights what was added, removed, or unchanged. Diffs are fundamental to version control systems like Git, code review workflows, and any situation where you need to track changes.
This tool shows a line-level diff: it finds the longest common subsequence of lines between the two inputs and marks the rest as additions or deletions. Inside changed regions, you can spot exactly what characters moved.
Common use cases include comparing contract versions, reviewing config changes, auditing text edits, and understanding what changed in exported documents.
Frequently Asked Questions
What kind of diff does this produce?
Line-level diff with character-level highlights inside changed lines. Both side-by-side and unified (git-style) views are available.
Can I ignore whitespace changes?
Yes. Enable the "Ignore whitespace" toggle to treat lines that differ only in whitespace as identical.
How does it handle very large documents?
For files up to a few hundred thousand lines, performance is fine in modern browsers. For truly massive files (millions of lines), desktop tools like diff, Meld, or Beyond Compare are better suited.
Does it work for code or just text?
It works for any text, including source code. The diff is content-agnostic — it compares lines character by character without understanding syntax.