Diff Checker
Compare two texts side-by-side. Instantly see what was added, removed, or unchanged.
Line-by-line comparison
The Diff Checker computes the Longest Common Subsequence between your two inputs and highlights insertions, deletions, and matching lines. It's ideal for comparing contract revisions, code snippets, configuration files, or any pair of documents. Everything runs in your browser — your text is never uploaded.
How the Diff Checker Works
This tool finds the differences between two blocks of text or code, line by line and word by word. Under the hood it uses algorithms like Longest Common Subsequence (LCS), which identify the portions shared by both texts and mark the remaining parts as added, removed, or modified.
The tool first splits both texts into lines, then compares each line against the other file's lines to determine which are identical and which differ. Where a line isn't entirely different but only a few words have changed, the tool drills down further and highlights just those changed words, so you don't need to re-read the whole line to spot the edit. Results are color-coded — typically green for additions and red for removals — making differences easy to scan at a glance.
This is useful for developers comparing two versions of code, writers tracking changes between drafts of a document, and anyone reviewing edits to legal or business documents where a single changed clause matters. The entire comparison runs in the browser, so sensitive text is never sent anywhere.