Regex AI Generator
Generate and test regex patterns from templates with real-time validation and multi-language export
Select Pattern Template
Regex Pattern
Test Your Pattern
Export Code
Recommended Settings
Common Pattern Templates
- •Email validation - Multiple variants from simple to RFC-compliant
- •Phone numbers - US, international formats with flexible spacing
- •URLs - HTTP/HTTPS with full path and query string support
- •Dates/Times - ISO, US, European formats for dates and 12/24 hour times
Flag Usage Guidelines
- •Global (g) - Find all matches instead of stopping at first match
- •Case Insensitive (i) - Match regardless of letter case
- •Multiline (m) - ^ and $ match start/end of lines, not just string
- •Dot All (s) - Dot (.) matches newline characters
Most Popular
Most patterns use case-insensitive flag for user input validation
When to Use This Tool
Validate user input in real-time for email addresses, phone numbers, passwords, and other form fields. Use the template library to quickly implement standard validation patterns with proven regex that handles edge cases and international formats.
Extract specific patterns from text, logs, or documents. Parse dates, URLs, phone numbers, or custom patterns from unstructured data. Test your regex with real examples to ensure accurate extraction before implementing in production code.
Find and replace patterns in code, configuration files, or text documents. Use capture groups to preserve parts of the match while transforming the rest. Test with multiline flag for processing multiple lines at once.
Clean user input by removing or validating specific patterns. Ensure usernames follow conventions, validate credit card formats (client-side only for UX), or enforce password complexity rules. Test edge cases to prevent bypassing validation.
How It Works
Select a category (Email, Phone, URL, etc.) from the dropdown
Choose a specific pattern variant that matches your needs
Review the pattern description and example matches
Customize the regex pattern if needed for your specific use case
Enable flags (global, case-insensitive, multiline, dot-all) as required
Enter test strings in the test input area (one per line)
Review real-time match results with visual indicators
Select your programming language and copy the export code
Download the pattern as JSON or copy to clipboard for use in your project
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Files never leave your device. All processing happens locally in your browser.
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Powered by Native JavaScript RegExp for optimal performance on modern browsers.
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Frequently Asked Questions
What's the difference between the regex flags?
Global (g) finds all matches in the text instead of stopping at the first one. Case Insensitive (i) ignores uppercase/lowercase differences. Multiline (m) makes ^ and $ match the start/end of each line rather than just the start/end of the entire string. Dot All (s) allows the dot (.) to match newline characters.
How do I test my regex pattern?
Enter test strings in the 'Test Input' section, one per line. The tool will automatically test your pattern against each line and show which ones match (green) or don't match (red). You'll see the actual matched text and any capture groups. Load examples to see how the selected template pattern works.
Can I customize the template patterns?
Yes! Select a template as a starting point, then edit the pattern directly in the regex pattern field. Any changes you make will be immediately tested against your test input. This is a great way to learn regex - start with a working template and modify it to understand how different parts affect matching.
What are capture groups and how do I use them?
Capture groups are parts of your regex enclosed in parentheses ( ). They let you extract specific portions of the match. For example, in a date pattern like (\d{2})/(\d{2})/(\d{4}), the three groups capture day, month, and year separately. The test results will show you what each group captured.
How do I use the exported code in my project?
Select your programming language from the 'Export Code' dropdown, then copy the generated code. In JavaScript, you can use it directly with .test() or .match(). In Python, import the re module first. Each language has slightly different syntax, which is why the tool provides language-specific export formats.
Why isn't my pattern matching what I expect?
Common issues: (1) Forgetting to escape special characters like . + * ? with a backslash, (2) Not using the global flag when you want all matches, (3) Not using case-insensitive flag for user input, (4) Anchors ^ and $ preventing partial matches. Use the test section to debug - it shows exactly what matched and what didn't.