無料正規表現テスター＆デバッガー | リアルタイムパターンマッチング

How It Works

1

Enter Your Pattern

Type a regular expression and select flags (g, i, m, s, u). Or pick from 20+ common patterns.

2

Add Test Text

Paste or type the text you want to test. Matches are highlighted in real-time as you type.

3

Analyze Results

See match count, highlighted text, capture groups, and match positions in a detailed table.

Why Use Our Regex Tester?

Real-Time Matching

Matches update instantly as you type. No submit buttons, no page reloads. See results immediately.

20+ Pattern Library

Common patterns for emails, URLs, phones, dates, colors, UUIDs, and more. One click to load and test.

Browser-Based & Private

All regex processing happens locally. No data sent to any server. Free, no signup, unlimited use.

Regex Tester & Debugger is a free, browser-based regular expression testing tool by Aibrify that provides real-time pattern matching, capture group display, and a library of 20+ common patterns. Built for developers, data analysts, and anyone working with text patterns.

What Are Regular Expressions?

Regular expressions (regex) are powerful text pattern matching sequences used across virtually every programming language. They enable searching, validating, and extracting text with precision — from simple email validation to complex log parsing and data extraction.

Common Use Cases for Regex

Input Validation: Verify email addresses, phone numbers, dates, and other formatted text
Data Extraction: Pull specific fields from logs, CSVs, HTML, and unstructured text
Search and Replace: Find and transform text patterns in code editors and scripts
Web Scraping: Extract structured data from web pages and API responses
Log Analysis: Parse server logs, error messages, and monitoring data

Regex Flags Explained

Flags modify how a regex pattern behaves: g (global) finds all matches; i (case-insensitive) ignores letter case; m (multiline) changes ^ and $ behavior; s (dotAll) makes . match newlines; u (unicode) enables full Unicode support.

Frequently Asked Questions

What regex flavor does this tool use?

This tool uses JavaScript's built-in RegExp engine, which follows the ECMAScript specification. It supports all modern flags including dotAll (s), unicode (u), and the standard global (g), case-insensitive (i), and multiline (m) flags.

What are capture groups and how do I use them?

Capture groups are portions of a regex pattern enclosed in parentheses (). They extract specific parts of a match. For example, the pattern (\d{4})-(\d{2})-(\d{2}) captures year, month, and day separately from a date string. Our tool displays each group's value in the match details table.

What does the global (g) flag do?

The global flag makes the regex find all matches in the text, not just the first one. Without it, only the first match is returned. Most use cases require the g flag to find every occurrence of a pattern.

How do I match across multiple lines?

Use the multiline (m) flag to make ^ and $ match the start and end of each line (not just the whole string). For matching any character including newlines, use the dotAll (s) flag, which makes the dot (.) match newline characters.

Can I use this for regex in other languages?

JavaScript regex syntax is very similar to other languages (Python, Java, PHP, Go). Most patterns are portable. However, some advanced features like lookbehind, named groups, and Unicode property escapes may differ between implementations.

Is this tool free?

Yes, 100% free with no limits. All processing happens in your browser using native JavaScript RegExp. No signup, no tracking, no data collection.

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正規表現テスター＆デバッガー -- リアルタイムパターンマッチング