Validate regular expressions against sample text with highlighted syntax matches.
Regex Tester & Matcher Guide
Validate regular expressions against test text in real-time. Features syntax highlighting, match statistics, and group capture explanations.
How to Test Regular Expressions:
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1
Input your regular expression pattern in the expression field.
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2
Select regex flags like global (g), case-insensitive (i), or multi-line (m).
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3
Type or paste your test text in the workspace below.
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4
The matcher highlights syntax matches and lists captured groups dynamically.
Regex Tester Capabilities:
Live Highlight Matches
Visual overlays showing pattern matches in your test text.
Captured Groups List
Displays all capturing groups and index bounds.
Syntax Check & Validation
Flags pattern errors and unescaped characters in real-time.
Flag Selector
Toggles for global, case-insensitive, multiline, unicode, and dotall modes.
Technical Specifications
| Specification | Details / Limits |
|---|---|
| Regex Engine | JavaScript RegExp (V8 compatible) |
| Supported Flags | g (global), i (insensitive), m (multi-line), s (dotall), u (unicode) |
| Output Details | Match count, index ranges, capturing groups |
Frequently Asked Questions
What is a regular expression (regex)?
A regular expression is a sequence of characters that forms a search pattern. It is used to check if a string contains a pattern, validate inputs, or replace text.
What is the global (g) flag used for?
The global flag (g) tells the regex engine to find all matches in the text, rather than stopping after the first match is found.
How does a capturing group work?
Wrapping part of a regex pattern in parentheses `( )` creates a capturing group. This extracts specific parts of a match for easy reference.