Replaces every occurrence of a search string in your text and reports how many replacements were made. By default matching is case-insensitive and literal; tick the boxes to require an exact case, match whole words only, or interpret the search string as a JavaScript regular expression.
In regex mode the replacement supports capture-group references such as $1 and $2, and an invalid pattern shows an error instead of running. Nothing is uploaded — all matching happens locally in your browser.