Regex Tester & Debugger

A regular expression is a sequence of characters that defines a search pattern. It is used in programming and text editors to find, match, and manipulate strings. Common use cases include input validation, data extraction, and search-and-replace operations.

Click the flag badges below the regex input to toggle them on or off. The "g" flag matches all occurrences instead of just the first. The "i" flag ignores letter casing. The "m" flag treats each line as a separate string for ^ and $ anchors.

Capture groups are portions of a pattern enclosed in parentheses. They let you extract specific parts of a match. Numbered groups are accessed by their position, while named groups use the syntax (?<name>...) and can be referenced by name in the results.

Yes! All processing happens entirely in your browser. Your regex patterns and test strings are never sent to any server. No data is collected, stored, or transmitted.

Yes. Enable the Replace mode toggle, enter your replacement string in the "Replace with" field, and the tool will show you the replaced output in real time. You can use backreferences like $1 or $<name> in the replacement string to insert captured groups.