Regex Tester Professional Regular Expression Testing Tool

Test and validate regular expressions with real-time pattern matching, capture group extraction, and comprehensive error reporting. Features common regex patterns, detailed explanations, and advanced testing capabilities for developers and data processors.

🎯 Pattern Matching

📋 Capture Groups

⚡ Real-time Testing

📥 Download DevHelper 👀 See Features

DevHelper Regex Tester Screenshot showing pattern matching with capture groups and real-time validation

Advanced Regex Testing Features

Everything you need for professional regular expression development, testing, and debugging.

🎯

Live Pattern Matching

Real-time regex matching with instant visual feedback. See matches highlighted in your test text as you type your regular expression pattern.

📋

Capture Groups

Extract and display capture groups with detailed breakdown. Perfect for parsing structured text, extracting data, and understanding complex patterns.

🏷️

Named Groups Support

Full support for named capture groups with clear labeling and extraction. Makes complex regex patterns more readable and maintainable.

⚠️

Error Detection

Comprehensive regex syntax validation with clear error messages and suggestions for fixing common regex pattern mistakes.

📚

Common Patterns Library

Pre-built regex patterns for emails, URLs, phone numbers, dates, and other common validation scenarios. Quick-start templates for developers.

🎛️

Regex Flags Support

Support for all standard regex flags including global (g), case-insensitive (i), multiline (m), and more for comprehensive pattern testing.

📊

Match Statistics

Detailed statistics showing match count, position information, and performance metrics for regex pattern optimization.

🔍

Replace & Substitute

Test regex replacement patterns with backreferences and substitution groups. Perfect for text processing and transformation workflows.

Common Regex Patterns

Ready-to-use regular expression patterns for common validation and extraction tasks

📧

Email Validation

^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$

Validates email addresses with proper format checking including domain and TLD requirements.

🌐

URL Matching

https?:\/\/(www\.)?[-a-zA-Z0-9@:%._\+~#=]{1,256}\.[a-zA-Z0-9()]{1,6}\b([-a-zA-Z0-9()@:%_\+.~#?&//=]*)

Matches HTTP and HTTPS URLs with optional www prefix and various URL parameters.

📱

Phone Numbers

^\+?1?-?\.?\s?$?([0-9]{3})$?[-.\s]?([0-9]{3})[-.\s]?([0-9]{4})$

Validates US phone numbers in various formats including international prefix and formatting.

📅

Date Formats

^(0[1-9]|1[0-2])\/(0[1-9]|[12][0-9]|3[01])\/\d{4}$

Matches MM/DD/YYYY date format with proper month and day validation ranges.

🆔

UUID Pattern

[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}

Validates UUID format with proper hyphen placement and hexadecimal character validation.

🔢

IP Address

^(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)$

Validates IPv4 addresses with proper octet range validation (0-255).

💳

Credit Card

^(?:4[0-9]{12}(?:[0-9]{3})?|5[1-5][0-9]{14}|3[47][0-9]{13}|3[0-9]{13}|6(?:011|5[0-9]{2})[0-9]{12})$

Validates major credit card formats including Visa, MasterCard, American Express.

🔒

Strong Password

^(?=.*[a-z])(?=.*[A-Z])(?=.*\d)(?=.*[@$!%*?&])[A-Za-z\d@$!%*?&]{8,}$

Validates strong passwords with lowercase, uppercase, numbers, and special characters.

How to Use Regex Tester

Test and validate regular expressions in just a few simple steps.

Enter Your Pattern

Type your regular expression pattern in the regex field. Use common patterns from our library or create your own custom pattern.

Add Test Text

Paste your test text that you want to match against the regex pattern. Can be single lines or multi-line text content.

Set Flags

Choose appropriate regex flags like global (g), case-insensitive (i), or multiline (m) based on your matching requirements.

View Results

See live matches highlighted, capture groups extracted, and detailed statistics about your regex pattern performance.

Perfect for These Development Tasks

✅

Data Validation

Validate user input like email addresses, phone numbers, postal codes, and other structured data formats in web forms and applications.

🔍

Text Processing & Parsing

Extract specific data from logs, configuration files, CSV data, or any structured text content using capture groups and pattern matching.

🔄

Search & Replace Operations

Perform complex text transformations, format conversions, and batch text processing using regex replacement patterns with backreferences.

📊

Log Analysis

Parse server logs, application logs, and error files to extract timestamps, IP addresses, error codes, and other relevant information.

🌐

Web Scraping

Extract data from HTML content, parse API responses, and clean up scraped text data using sophisticated pattern matching.

⚙️

Configuration & Routing

Create URL routing patterns, validate configuration parameters, and process template strings in web frameworks and applications.

Frequently Asked Questions

What regex flags are supported?

DevHelper supports all standard regex flags: global (g), case-insensitive (i), multiline (m), dotall (s), unicode (u), and sticky (y). These flags modify how your regex pattern behaves.

Can I test replacement patterns?

Yes! The regex tester includes replacement functionality with support for backreferences ($1, $2, etc.) and named group references for complex text transformations.

How do I use capture groups effectively?

Use parentheses () to create capture groups. Named groups (?pattern) are even better for readability. DevHelper shows all captured groups with their values clearly.

What happens with invalid regex patterns?

DevHelper provides clear error messages for invalid regex syntax, including suggestions for common mistakes like unescaped special characters or unclosed groups.

Can I test regex against large text files?

The regex tester is optimized for reasonably sized text content. For very large files, consider testing with smaller samples first to verify your pattern works correctly.

Are there performance warnings for complex patterns?

DevHelper provides basic performance feedback and will warn about potentially problematic patterns that might cause excessive backtracking or slow execution.