How Text Comparison Works
A diff algorithm breaks both versions into lines, words, or characters and finds an ordered sequence they share. Anything present only in the original is marked as removed, while anything found only in the revised version is marked as added. Adjacent removals and additions represent a modified section.
Removed
Content found only in the original.
Added
Content found only in the revision.
Unchanged
Content shared by both versions.
Choosing the Right Comparison Detail
Line comparison
Best for source code, documents, logs, lists, and configuration files.
Word comparison
Best for edited sentences, articles, reports, and rewritten paragraphs.
Character comparison
Best for short text where spelling, punctuation, or exact formatting matters.
Common Uses for a Diff Checker
- Review edits between document drafts
- Compare code or configuration changes
- Check rewritten SEO and marketing copy
- Inspect assignment or report revisions
- Find differences between JSON, CSV, XML, or logs
- Create a portable unified .diff report
Case and Whitespace Options
Ignoring case is useful when capitalization is not meaningful. Ignoring whitespace helps when indentation or repeated spaces should not count as changes. These settings affect matching and similarity statistics, but the editor keeps the original pasted content unchanged.
Private Browser-Based Comparison
Both text versions and uploaded files are processed locally in your browser. No text is sent to a comparison server. Review downloaded reports before sharing them because they may contain both old and new sensitive content.