Real-Time Regex Tester
Validate and test regular expression patterns against target subject strings. View captures, matches, and subgroups in real time.
Regular Expression
//gi
Test Subject Text
Match Highlights0 Matches
Highlighted test results will display here...
Capture Groups & Indices
No active matches found. Capture groups will populate when patterns match.
Frequently Asked Questions
Regex Cheatsheet & Syntax Reference
A Regular Expression (Regex) is a sequence of characters that forms a search pattern. It is used to validate strings (like checking email formats), search text blocks, and extract capturing subgroups.
Quantifiers
*0 or more times
+1 or more times
?0 or 1 time (optional)
{n,m}Between n and m times
Character Classes
[a-z]Lowercase letters
\dAny digit (0-9)
\wWord character (a-z, 0-9, _)
\sWhitespace character
Regex Flags Explained
Flags modify the parsing behavior of regular expression engines:
- Global (g): Finds all matching patterns in the input text instead of stopping after the first match.
- IgnoreCase (i): Ignores case specifications. E.g.
/[a-z]/imatches lowercase and uppercase letters. - Multiline (m): Directs boundary anchors (
^and$) to match start/end of lines instead of start/end of the entire string. - DotAll (s): Allows wildcard dots (
.) to match newline characters as well.