Regex 테스터
정규 표현식을 테스트하고 디버그합니다
사용 방법
텍스트 붙여넣기 또는 입력
입력 영역에 텍스트, 코드 또는 데이터를 입력하세요.
옵션 선택
적용할 변환이나 포맷을 선택하세요.
결과 복사
한 번의 클릭으로 출력을 클립보드에 복사하세요.
이 도구를 사용하는 이유
100% 무료
숨겨진 비용도, 프리미엄 등급도 없습니다 — 모든 기능이 무료입니다.
설치 불필요
브라우저에서 완전히 실행됩니다. 소프트웨어를 다운로드하거나 설치할 필요가 없습니다.
프라이빗 & 안전
데이터가 기기 밖으로 나가지 않습니다. 어떤 서버에도 업로드되지 않습니다.
모바일 지원
완전 반응형 — 스마트폰, 태블릿, 데스크톱에서 사용할 수 있습니다.
Regular Expressions: Pattern Matching Mastery
Key Takeaways
- Regular expressions provide powerful pattern matching for text validation, extraction, search, and transformation.
- Understanding regex quantifiers, character classes, groups, and lookaheads is essential for writing efficient patterns.
- All regex testing runs in your browser — your test data is never sent to any server.
Regular expressions (regex) are one of the most powerful tools in a developer's toolkit, enabling complex text pattern matching in a single expression. From validating email addresses and parsing log files to extracting data from unstructured text, regex is used across virtually every programming language and text processing tool. Mastering regex dramatically increases productivity in text-heavy development tasks.
Regular expressions are supported natively in over 30 programming languages and virtually every text editor.
Universal Support
Key Concepts
Character Classes and Quantifiers
Character classes ([a-z], \d, \w, \s) match categories of characters. Quantifiers (*, +, ?, {n,m}) control how many times a pattern repeats. Combining them creates powerful matchers.
Capture Groups and Backreferences
Parentheses create capture groups that extract matched substrings. Named groups (?<name>...) improve readability. Backreferences (\1 or \k<name>) match the same text again.
Lookaheads and Lookbehinds
Lookahead (?=...) and lookbehind (?<=...) assert that text exists before or after the match without including it in the result. Negative versions (?!...) and (?<!...) assert absence.
Greedy vs. Lazy Matching
By default, quantifiers are greedy (match as much as possible). Adding ? makes them lazy (match as little as possible). This distinction is critical for avoiding over-matching in complex patterns.
Pro Tips
Start with a simple pattern and incrementally add complexity — debugging a complex regex all at once is extremely difficult.
Use non-capturing groups (?:...) when you need grouping for alternation or quantifiers but do not need to capture the match.
Beware of catastrophic backtracking — nested quantifiers like (a+)+ on non-matching input can cause exponential processing time.
Use the 'u' flag in JavaScript regex for proper Unicode handling, especially when working with international text.
All regular expression testing is performed entirely in your browser using JavaScript's built-in RegExp engine. Your test strings and patterns are never transmitted to any server.