Online text search and replace

Standard JavaScript (RegExp) syntax is supported. The script builds the expression with the g and u flags, and when "Match case" is off, it also adds i.

What works

• Classes and quantifiers: \d, \s, [abc], [^abc], +, *, ?, {2,5}, lazy +?, *?.
• Groups and references: (...), (?:...), (?<name>...), backreference \1.
• Lookahead and lookbehind: (?=...), (?!...), (?<=...), (?<!...).
• Unicode properties: \p{L} (any letter), \p{Lu} (uppercase letter), \p{N} (digit). \p{Cyrillic} does not work, use \p{Script=Cyrillic} instead.
• In the replacement field: $1, $& (the whole match), $<name>, $$ (a dollar sign).

Examples

• All numbers: find \d+.
• Collapse multiple spaces into one: find \s{2,}, replace with a single space.
• Date DD.MM.YYYY to YYYY-MM-DD: find (\d{2})\.(\d{2})\.(\d{4}), replace with $3-$2-$1.
• Same with named groups: find (?<d>\d{2})\.(?<m>\d{2})\.(?<y>\d{4}), replace with $<y>-$<m>-$<d>.
• Links: find https?://\S+.
• E-mail: find [\w.+-]+@[\w-]+\.[\w.-]+.
• Words in capital letters (any language): find \p{Lu}{2,}.
• Repeated word in a row: find (\p{L}+) \1, replace with $1.
• Wrap a match in quotes: find word, replace with "$&".
• The word "cat" but not "catalog": find cat(?!\p{L}).
• Price after the ₽ sign: find (?<=₽)\d+.
• Remove HTML tags: find <[^>]+>, leave the replacement field empty.

Limitations

• \b and \w do not recognize Cyrillic. They work only with Latin letters, digits and _. For Cyrillic text use \p{L} or [а-яё], and for word boundaries use the "Whole word" checkbox (it is built on \p{L}).
• ^ and $ mean the start and end of the entire text, not of a line: there is no m flag. So ^\s+|\s+$ removes spaces only at the edges of the whole text.
• The dot . does not match a line break, and there is no s flag. To match "any character, including line breaks", use [\s\S].
• The u mode is stricter than the default. Unnecessary escaping such as \- or \_ outside a character class causes an "Invalid regular expression" error. Escape only special characters.
• In the replacement field, \n and \t are not interpreted and are inserted as literal characters. The field is single-line, so a line break cannot be entered there. In the search field, \n and \t work.
• $` and $' are not supported in the replacement, nor are flags written in the /abc/gi style: no slashes are needed, enter only the pattern itself.
• Limit: no more than 5000 matches are highlighted.

Quick step-by-step guide: paste your text, enter what to find and what to replace it with, then click "Replace" or "Replace all".

A ready-to-use example with \s{2,}. This is one of the most common requests.

Searching for \n in regex mode will help - replace it with a space.

Your text is never sent anywhere, but if you click "Save text to history", it will be saved to your account and you can delete it later.