Do I need to include / delimiters?

No. Enter the pattern only (e.g., \d+ not /\d+/g). Set flags separately in the flags field.

What flags are supported?

g (global), i (case-insensitive), m (multiline), s (dotAll), u (unicode). Combine them like 'gi'.

Parentheses in a regex create capture groups. For example, (\d{3})-(\d{4}) captures the area code and number separately.

No. Regex matching runs entirely in your browser using JavaScript's native RegExp engine.

Developer Tools

Test regular expressions against sample text in real time. See matches, capture groups, and match positions instantly.

PatternFlags

Test String

1 line • 40 chars

Paste test text, keep line numbers visible, and inspect matches or regex errors without leaving fullscreen mode.

Quick examples

Matches (2)

#1 @5555-123-4567

$1: 555$2: 123$3: 4567

#2 @21800-555-0199

$1: 800$2: 555$3: 0199