Regex Tester
See what a regular expression actually matches as you type it. Capture groups and named groups are laid out in a table.
How to use
Type the pattern in the top field and paste the text you want to check underneath it. Matches are listed as you type, along with the character offset where each one starts.
Flags are checkboxes. g finds every match instead of stopping at the first one, i ignores case, m makes ^ and $ line up with the start and end of each line, and s lets the dot match newlines as well.
Anything you wrap in parentheses shows up in the groups column, in order. Named groups are listed as name and value, which makes it easy to confirm that a log line or a date string is being pulled apart the way you expect.
The pattern and the text stay in your browser. Nothing is sent to a server, so you can test against real log output.