Test and debug regular expressions
Test and debug regular expressions
Hint: use $1 through $9 for capture groups and $& for the whole match. The global (g) flag is applied automatically so every match is replaced.
. - Any character\d - Digit [0-9]\w - Word [a-zA-Z0-9_]\s - Whitespace* - 0 or more+ - 1 or more? - 0 or 1{n,m} - Between n and m^ - Start of string$ - End of string() - Capture group(?:) - Non-capture groupEnter a replacement string in the Replace Matches box and click Replace All. The tool compiles your pattern with the chosen flags, adds the global flag automatically so every match is replaced, and shows the finished output together with the total replacement count and a Copy Output button.
Yes. Use $1 through $9 to insert the numbered capture groups from your pattern, and $& to insert the entire matched text. Wrapping a group in new text is just a matter of typing the surrounding characters around $1 in the replacement field.
Four checkboxes control the flags: g for finding all matches, i for case insensitive matching, m to make the start and end anchors work per line, and s to let the dot match newlines. Invalid patterns show an inline error, while valid ones highlight matches in real time and list every match value, position, and group in the details panel.
The Email, URL, and Phone buttons above the pattern field load a ready-made regular expression along with a matching sample test string, so highlighting, match details, and replace behavior can be explored immediately. You can also copy the current pattern with its flags or export the session results as a JSON file.
No. Matching and replacing run on the RegExp engine built into your browser, so the text never leaves the page. The export option only writes a local JSON file when you click it yourself.