Compare two blocks of text and see exactly what changed — additions highlighted green, deletions highlighted red.
Also search and replace text with our Find & Replace tool or test patterns with the Regex Tester.
🔒 Your text is processed locally — nothing is stored or uploaded.
A diff checker compares two versions of text and highlights what has changed between them. Added lines appear in green and removed lines appear in red, mirroring the output of the git diff command used by developers to review code changes before committing. This diff checker tool works as an online text comparison tool, code diff viewer, and document change tracker for developers, writers, and anyone who needs to understand what changed between two versions of a document.
Developers use diff checkers when reviewing changes to configuration files, SQL migration scripts, or environment variable files that are not tracked in version control. When a colleague sends an updated config by email or paste, comparing it against the current version in a diff checker immediately highlights the specific lines that changed — rather than reading both files in full to spot the difference manually.
Technical writers and content editors use diff checkers when reviewing document revisions. When an editor returns a revised version of a specification, user guide, or policy document, running a diff comparison shows exactly which sentences were added, which were removed, and which are unchanged — giving a clear picture of the scope of the changes without needing tracked changes in a word processor.
QA engineers use diff checkers to compare API response snapshots. When testing whether a code change affected API output, pasting the before and after JSON responses into a diff checker immediately reveals which fields changed, which were added, and which were removed. This is faster than reading two long JSON payloads side by side and mentally tracking the differences. All comparison runs in your browser — your text is never sent to any server.