Text Diff

Compare two text documents side-by-side or inline to highlight additions, deletions, and line-by-line or character-by-character differences. Typical uses include comparing drafts of essays, contracts, and legal documents, reviewing code changes and configuration files, and verifying revisions between two versions of text. The focused Text Diff workflow is intended for people who need a dependable result without opening a larger desktop application or creating an account for a one-off task.

Implements Myers Diff algorithm and Longest Common Subsequence (LCS) in JavaScript to produce token-level differential arrays. Its controls cover side-by-side and unified inline diff views, character-level and word-level difference highlighting, line numbers and change summary counter (added/removed lines), synchronized scrolling between comparison panels, and 100% private in-browser comparison. The tool accepts original Text, and Changed Text. It produces diff View that can be reviewed before it is saved.

Comparing extremely large text files (>50,000 lines) may require a few seconds of client-side CPU computation. When Text Diff is marked as in-browser, its work remains on the current device; available memory, processor speed, browser support, permissions, and source quality can still affect the result. Keep the original material supplied to Text Diff until its diff View has been checked for the intended use.