🔧 Regex Tester

Create patterns for log analysis, file filtering, configuration parsing, and automated text processing tasks

Regular Expression Pattern:

Enter the regex pattern to test (without delimiters)

Test Text:

The text content where you want to find matches

Regex Flags:

Regex flags: g=global, i=ignoreCase, m=multiline, s=dotAll, u=unicode, y=sticky

Show Capture Groups:

Display captured groups for each match

Show Capture Groups

Show Match Positions:

Show start and end positions of matches

Show Match Positions

Case Sensitive:

Make the regex case sensitive (overrides 'i' flag)

Case Sensitive

Regex Test Results:

🔍 Sample Regex Test Results

Email Pattern Test

\b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b

2 matches found in test text

Flags: g (global) • Groups: enabled

Match Results

✅ support@example.com (position 12-30)

✅ sales@company.org (position 34-51)

Pattern Analysis

Valid regex pattern • Global matching enabled

Use this tool to test your own patterns

🔧

JavaScript Required:

⚠️ JavaScript Required

This regex tester requires JavaScript to function. Please enable JavaScript in your browser to test regex patterns.

Example Pattern Test:

Pattern: \b[A-Za-z0-9._%+-]+@[A-Za-z0-9.-]+\.[A-Z|a-z]{2,}\b

Would match email addresses in text

How to Use This Regex Tester

Basic Usage:

Fill in the required fields above
Adjust any optional settings as needed
Click the button to generate your result
Copy or download the output

Tips: This regex tester provides instant results and works entirely in your browser for privacy.

How It Works

Our regex tester uses JavaScript's built-in RegExp engine to test patterns against text, providing detailed match information and visual feedback.

🔍 Pattern Matching

• Real-time pattern compilation and testing
• Support for all JavaScript regex features
• Visual highlighting of matches in text
• Detailed error reporting for invalid patterns

📊 Match Analysis

• Capture group extraction and display
• Match position and length information
• Multiple match handling with global flag
• Flag combination effects visualization

When You Might Need This

• Development & Debugging: Test regex patterns for form validation, data parsing, string manipulation, and input sanitization in your applications
• Data Processing: Validate and extract structured data from text files, logs, CSV files, or API responses with complex patterns
• Text Analysis: Search and analyze large text documents, extract specific information patterns, or validate data formats
• Learning & Education: Understand regex behavior, experiment with pattern matching concepts, and debug complex expressions
• System Administration: Create patterns for log analysis, file filtering, configuration parsing, and automated text processing tasks

Frequently Asked Questions

What regex flavor does this tester use?

This tester uses JavaScript's native RegExp engine, which follows ECMAScript specifications. It supports most common regex features including lookaheads, lookbehinds, character classes, quantifiers, and Unicode support. Some advanced features from other flavors like PCRE may not be available.

How do I test for multiple lines or special characters?

Use the 'm' flag for multiline mode to make ^ and $ match line boundaries, and 's' flag for dotAll mode to make . match newlines. For special characters, use proper escaping with backslashes. The tester will show you exactly what matches and where.

Why isn't my regex pattern matching what I expect?

Common issues include: missing the global 'g' flag for multiple matches, incorrect escaping of special characters, case sensitivity when 'i' flag is needed, or pattern anchors (^ $) being too restrictive. Use the position and group display features to debug your pattern step by step.

Can I test complex patterns with capture groups?

Yes! Enable "Show Capture Groups" to see all captured groups for each match. This is perfect for patterns that extract multiple pieces of data, like parsing dates, emails, or structured text. Named capture groups (?<name>pattern) are also supported and displayed.