Text comparison tool shows the exact differences between two blocks of text at a glance. This free, browser-based utility highlights every addition and deletion so you can review changes without manually scanning line by line. No signup required. Useful for writers, editors, developers, and anyone who needs to audit changes between two versions of content.
The Text Diff Checker compares two texts side by side and highlights the differences, showing additions in green and deletions in red. This is useful for comparing two versions of a document, reviewing changes in a configuration file, checking that a translation preserved all the original content, or verifying that a text was copied correctly. The comparison is done at the word level by default (highlighting individual changed words within lines) or at the line level (marking entire changed lines). You can switch between inline view (showing both versions in a single column with changes marked) and split view (showing original on the left and modified on the right). The tool shows a summary of how many lines were added, removed, and unchanged. All processing runs in your browser with no data sent to any server.
Text diff tools are essential for any workflow involving document revisions, content review, or configuration management. The algorithm behind most diff tools is the Longest Common Subsequence (LCS) algorithm, which finds the longest sequence of lines (or characters) that appear in both texts in the same order, then marks everything outside the LCS as either an addition or a deletion. This is the same algorithm used by git diff and most code review tools. At the word level, word-by-word diffing produces more readable output than character-by-character diffing for prose text: if a sentence changes from "The quick brown fox" to "The fast brown fox", word-level diff shows "quick" deleted and "fast" added, while character-level diff would show multiple character changes that are harder to read. For legal documents and contracts, diff tools are essential when reviewing revisions: the ability to see exactly what changed between a draft and a revised version, at both the word and line level, makes contract review much more reliable. For configuration files, the line-level diff is often more appropriate because each line is a distinct configuration value and adding or removing a single property is a meaningful change. For translated documents, comparing the original and translation side by side with diffing can help catch accidentally omitted paragraphs or duplicated sections.