テキスト差分チェック

This text diff checker compares two blocks of text and highlights exactly what changed: which lines were added, which were removed, and the specific words within a changed line. Green marks additions, red marks removals.

Because the comparison runs entirely in your browser, it is fast and private, suitable even for confidential documents and code that you would not want to paste into a server-side service.

It uses a longest-common-subsequence diff, the same core algorithm Git and most code-review tools use, so it reports the smallest, clearest set of changes rather than flagging everything after the first difference.

Options let you ignore case or whitespace, which is useful when the only real differences are meaningful ones and you do not want indentation changes or capitalization to clutter the result.

Line-based diffing works equally well for source code, configuration files, logs, JSON, and ordinary prose, so it is handy for comparing two versions of a contract, spotting what changed between two config files, or reviewing an edit to an article.

Paste the original on one side and the changed version on the other, toggle the options you need, and the differences appear immediately.