How to use find and replace
Paste your text, type what to find and what to replace it with, and the result updates instantly along with a count of how many replacements happened. Three toggles control the match: "match case" makes the search case-sensitive so "Cat" and "cat" are treated differently, "whole word only" prevents partial matches so replacing "cat" leaves "category" untouched, and "use regular expression" switches the find field into full pattern-matching mode. Copy the cleaned text when you are done.
Whole-word matching explained
The most common find-and-replace mistake is an unwanted partial match. If you replace "cat" with "dog" in a normal search, you also turn "category" into "dogegory" and "concatenate" into "condogenate". Whole-word matching fixes this by requiring a word boundary on each side of the match, so only the standalone word "cat" is replaced and longer words that merely contain those letters are left alone. Turn it on whenever you are swapping a real word rather than a fragment, and leave it off when you genuinely want to change part of longer words.
What regular expressions unlock
With the regex toggle on, the find field accepts a regular expression — a compact pattern language for describing text. This lets you do things a plain search cannot: match any run of digits with \d+, collapse repeated spaces, reformat dates, strip everything inside brackets, or capture part of a match and reuse it in the replacement with $1 and $2. For example, finding (\w+)@(\w+) and replacing with $2 at $1 rewrites the two halves of a simple token. Regex is powerful and worth learning, but it is also easy to over-match, so always check the replacement count and preview before trusting a complex pattern.
Practical uses and tips
Writers use it to change a character or product name consistently across a whole document. Developers reformat data, swap delimiters, and clean exports. Editors standardise spelling — turning every "color" into "colour" or every straight quote into a curly one — in a single pass. When you are unsure whether a replacement is safe, do it on a copy first and watch the count: if the number is far higher than you expected, you are probably matching inside longer words, so switch on whole-word matching. For case-sensitive data like codes and identifiers, turn on match case to avoid clobbering something that only differs by capitalisation. And because the whole operation runs in your browser, even a large document is replaced instantly with nothing uploaded.