Developer Tool Guide
Regex Tester & Regular Expression Debugger
Regular expressions (regex) are essential for parsing text, validating forms, and tokenizing input. However, crafting precise patterns without unintended catastrophic backtracking or missing edge-cases can be difficult.
Test Your Regex Right Now
Launch our high-performance Vue 3 interactive tool with live match indexing and regex substitution.
🚀 Open Interactive Regex TesterJavaScript Regex Cheat Sheet
\d Matches any digit (0-9)
\w Matches any word character (alphanumeric + underscore)
\s Matches any whitespace character (space, tab, newline)
. Matches any character except line breaks (unless /s flag is active)
^ Asserts start of string (or start of line in /m multiline mode)
$ Asserts end of string (or end of line in /m multiline mode)
[abc] Character set: matches either 'a', 'b', or 'c'
[^abc] Negated character set: matches anything except 'a', 'b', or 'c'
(x) Capturing group: remembers match for replacement ($1, $2)
(?:x) Non-capturing group: groups characters without memory overhead
(?<name>x) Named capturing group
+ Quantifier: 1 or more times
* Quantifier: 0 or more times
? Quantifier: 0 or 1 time (or lazy modifier when following + or *)
{n,m} Quantifier: between n and m times
Common Regex Flags
g(Global): Find all matches rather than stopping at the first occurrence.i(Case-Insensitive): Match regardless of uppercase or lowercase distinctions.m(Multiline): Makes^and$match the beginning and end of each individual line.s(DotAll): Allows the dot.character to match newline characters.u(Unicode): Treats the pattern as a sequence of Unicode code points.
Frequently Asked Questions
Is my test data uploaded to any server?
No. All regex compilation and string testing is executed strictly in your browser using JavaScript's native
RegExp engine.
What regex flavor is used?
The tester utilizes modern ECMAScript standard regex including named capture groups, lookbehind assertions, and unicode property escapes.