How to use
Test regular expressions and see matches instantly
Enter a regular expression pattern and test it against sample text. See which parts match, get detailed match information, and understand your regex pattern better.
Perfect for validating patterns, learning regex, and debugging complex expressions.
Syntax Reference
Reference updates based on selected method. Note: Patterns run as JavaScript; some features may differ from native implementations.
Character Classes
- .
- Any character except newline
- \\d
- Digit (0-9)
- \\w
- Word character (a-z, A-Z, 0-9, _)
- \\s
- Whitespace
- [abc]
- a, b, or c
Groups & Flags
- (abc)
- Capturing group
- (?:abc)
- Non-capturing group
- (?<name>...)
- Named group
- g, i, m, s, u, y
- Flags: Global, ignore case, multiline, dotAll, unicode, sticky
Quantifiers
- *
- 0 or more
- +
- 1 or more
- ?
- 0 or 1
- {n,m}
- Between n and m times
Anchors & Assertions
- ^
- Start of line/string
- $
- End of line/string
- \\b
- Word boundary
- |
- OR - alternation
Character Classes
- .
- Any character except newline (unless DOTALL)
- \\d
- Digit (0-9)
- \\w
- Word character (a-z, A-Z, 0-9, _)
- \\s
- Whitespace
- [abc]
- a, b, or c
Named Groups (Python)
- (?P<name>...)
- Named group (Python syntax)
- (?P=name)
- Backreference to named group
- (?:abc)
- Non-capturing group
- (abc)
- Capturing group
Quantifiers
- *
- 0 or more
- +
- 1 or more
- ?
- 0 or 1
- {n,m}
- Between n and m times
Flags (re.CONSTANT)
- re.I, re.IGNORECASE
- Case-insensitive matching
- re.M, re.MULTILINE
- ^ and $ per line
- re.S, re.DOTALL
- Dot matches newline
- re.X, re.VERBOSE
- Ignore whitespace/comments
Character Classes
- .
- Any character except newline (unless /s)
- \\d
- Digit (0-9)
- \\w
- Word character
- \\s
- Whitespace
- \\h, \\v
- Horizontal/vertical whitespace
Named Groups & Advanced
- (?<name>...)
- Named group
- (?<=...)
- Positive lookbehind
- (?<!...)
- Negative lookbehind
- (?>...)
- Atomic group
Quantifiers
- *
- 0 or more (greedy)
- +
- 1 or more (greedy)
- *?, +?
- Non-greedy versions
- {n,m}
- Between n and m times
Flags (modifiers)
- i, m, s, x
- Case-insensitive, multiline, dotAll, extended
- U
- Ungreedy (inverts quantifiers)
- A, D
- Anchors at start/end only
Character Classes
- .
- Any character except newline (unless /s)
- \\d
- Digit (0-9)
- \\w
- Word character
- \\s
- Whitespace
- \\p{L}
- Unicode letters (if /u flag)
Named Groups (Perl Syntax)
- (?P<name>...)
- Named group (Perl-compatible)
- (?<=...)
- Positive lookbehind
- (?<!...)
- Negative lookbehind
- (?:abc)
- Non-capturing group
Quantifiers
- *
- 0 or more
- +
- 1 or more
- ?
- 0 or 1
- {n,m}
- Between n and m times
Flags (PCRE modifiers)
- i, m, s, x
- Case-insensitive, multiline, dotAll, extended
- u
- Unicode support
- A, D, U
- Anchors, end-of-string, ungreedy