Regex Pattern Generator
Build and test regular expressions with 10+ templates, live validation, and pattern explanations—perfect for developers.
About Regular Expressions
Regular expressions (regex) are patterns used to match character combinations in strings. They're essential for validation, search, and text processing in programming. Use our templates above to get started quickly!
Our Regex Pattern Generator is a comprehensive free tool for creating and testing regular expressions with 10+ pre-built templates. Perfect for developers validating emails, phone numbers, passwords, URLs, and custom patterns, it provides live testing, automatic pattern breakdowns, and flag configuration—all processed in your browser.
Common Use Cases for Regex Patterns
- ✓Form Validation
Create regex patterns to validate user inputs like emails, phone numbers, passwords, and credit cards in web forms.
- ✓Data Extraction
Extract specific patterns from log files, CSV data, or text documents using custom regex patterns.
- ✓Input Sanitization
Build patterns to filter and sanitize user input, preventing SQL injection or XSS attacks in applications.
- ✓Search & Replace
Create patterns for find-and-replace operations in code editors, text processors, or data transformation scripts.
- ✓API Validation
Validate API request parameters, route patterns, and response data formats using regex in backend services.
- ✓Log Parsing
Parse server logs, error logs, or application logs to extract timestamps, error codes, or specific events.
Why Choose Our Regex Generator?
10+ Pattern Templates
Pre-built patterns for email, phone, password, URL, IP, hex color, username, date, ZIP code, and credit card
Live Testing
Test patterns against multiple strings simultaneously with instant pass/fail feedback
Pattern Breakdown
Automatic explanation of regex components like anchors, quantifiers, character classes, and lookaheads
Flag Support
Configure global (g), case-insensitive (i), and multiline (m) flags for flexible matching
Line-by-Line Results
See which test strings match or fail with color-coded results and line numbers
Export & Share
Download patterns with test results or copy to clipboard for use in your code
How to Use the Regex Pattern Generator
- Choose Template: Click a quick template badge (Email, Phone, Password, etc.) or enter custom pattern
- Configure Flags: Set global (g), case-insensitive (i), or multiline (m) flags as needed
- Add Test Data: Enter test strings (one per line) to validate your pattern
- View Results: See color-coded pass/fail results with match counts
- Read Breakdown: Review automatic pattern explanation showing what each component does
- Copy or Download: Copy pattern to clipboard or download with test results
Regex Pattern Cheat Sheet
Character Classes
\d- Any digit (0-9)\w- Word character (a-z, A-Z, 0-9, _)\s- Whitespace (space, tab, newline).- Any character except newline[abc]- Any of a, b, or c[^abc]- Not a, b, or c
Quantifiers
*- 0 or more+- 1 or more?- 0 or 1 (optional){n}- Exactly n times{n,m}- Between n and m times{n,}- n or more times
Anchors
^- Start of string/line$- End of string/line\b- Word boundary\B- Not word boundary
Groups & Lookahead
(abc)- Capture group(?:abc)- Non-capturing group(?=abc)- Positive lookahead(?!abc)- Negative lookaheada|b- OR operator
Code Examples
JavaScript
// Test email pattern
const emailRegex = /^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$/;
const email = "user@example.com";
console.log(emailRegex.test(email)); // true
// Extract all matches
const text = "Call 555-123-4567 or 555-987-6543";
const phoneRegex = /\d{3}-\d{3}-\d{4}/g;
const matches = text.match(phoneRegex);
console.log(matches); // ["555-123-4567", "555-987-6543"]Python
import re
# Test pattern
email_pattern = r'^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$'
email = "user@example.com"
match = re.match(email_pattern, email)
print(bool(match)) # True
# Find all matches
text = "Call 555-123-4567 or 555-987-6543"
phone_pattern = r'\d{3}-\d{3}-\d{4}'
matches = re.findall(phone_pattern, text)
print(matches) # ['555-123-4567', '555-987-6543']Frequently Asked Questions
What is a regex pattern generator?
A regex pattern generator is a tool that helps you create and test regular expressions (regex) for pattern matching in strings. It provides templates for common patterns like emails, phone numbers, and passwords, along with live testing to verify your regex works correctly before using it in code.
How do I validate email addresses with regex?
Use the Email template in our tool, which provides the pattern: ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$. This matches standard email formats like user@example.com. For production use, consider more comprehensive validation or email verification services, as regex alone can't catch all edge cases.
What are regex flags and when should I use them?
Regex flags modify pattern behavior: 'g' (global) finds all matches instead of just the first, 'i' (case-insensitive) ignores letter case, and 'm' (multiline) treats ^ and $ as line boundaries. Use 'g' for finding multiple occurrences, 'i' for flexible text matching, and 'm' for multi-line text processing.
Can I test my regex pattern before using it in code?
Yes! Enter your pattern in the 'Regex Pattern' field, add test strings (one per line) in the 'Test Text' area, and see instant results. Green indicates matches, red indicates failures. The tool also shows a pattern breakdown explaining each component of your regex.
What's the difference between this and a regex validator?
A regex generator helps you BUILD patterns with templates and explanations, while a validator helps you TEST existing patterns with detailed match highlighting and capture groups. Use the generator to create patterns, then use our Regex Validator tool for in-depth testing and debugging.
Are these regex patterns compatible with all programming languages?
Most patterns work across JavaScript, Python, PHP, Java, and C# with minor syntax differences. JavaScript uses /pattern/flags format, Python uses r'pattern', and some languages have different escape sequences. Always test patterns in your target language's environment for production use.