Regex Generator
Free online regex generator. Generate regex patterns for email validation, URL matching, phone numbers, dates, IP addresses and more. Copy-ready patterns for JavaScript, Python and PHP.
Select a pattern type and click Generate
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Generate a pattern first, then enter test text.
How to Use Regex Generator
Choose a Pattern Type
Select the type of regex you need — email, URL, phone number, date, IP address, or custom patterns. Each type generates a battle-tested pattern commonly used in production.
Customize Options
Adjust settings specific to your pattern type — allow/disallow subdomains for URLs, choose date format for dates, select phone number format. The generated regex updates automatically.
Copy and Test
Copy the generated regex pattern. Use it in your JavaScript, Python, or PHP code. Test it immediately in the built-in tester with sample text to verify it matches correctly.
Example Generated Patterns
| Type | Example Match |
|---|---|
| [email protected] | |
| URL | https://example.com/path |
| Phone (US) | (555) 123-4567 |
| Date (YYYY-MM-DD) | 2025-01-15 |
| IPv4 | 192.168.1.1 |
| Hex Color | #3b82f6 |
| ZIP Code (US) | 90210 |
| Username | john_doe_42 |
Click "Generate" to see the actual regex pattern for each type. Patterns are generated as standard JavaScript-compatible regex with copy-ready code snippets.
Frequently Asked Questions
Can I trust generated regex patterns?
The patterns we generate are based on widely-used, tested regex patterns from the developer community. They handle the most common cases correctly, but no regex is perfect for every edge case. Email validation via regex is particularly tricky — the official RFC 5322 email regex is over 200 characters. Our patterns are practical, not academic. Always test against your real data before deploying to production.
Why generate regex instead of writing it manually?
Regex is tedious to write and easy to get wrong. A misplaced quantifier or escaped character produces subtly incorrect matches that might not be caught in testing. Generating patterns from validated templates is faster and more reliable for common tasks. For uncommon or highly specific patterns, use our Regex Tester to build and test iteratively.
What is the difference between greedy and lazy matching?
Greedy quantifiers (*, +) match as much text as possible while still allowing the overall pattern to match. Lazy quantifiers (*?, +?) match as little as possible. For example, with the text "hello world", the pattern "h.*o" (greedy) matches "hello wo" while "h.*?o" (lazy) matches "hello". The generated patterns use the appropriate quantifier for each use case.
How do I handle international formats?
International phone numbers, addresses, and names vary enormously in format. Our generated patterns target common formats (US phone numbers, standard email formats) but may need modification for international use. For phone numbers specifically, consider using a parsing library like libphonenumber instead of regex — it handles 200+ country formats correctly.
When Generated Regex Is Enough
Generated regex patterns cover 95% of real-world use cases. Form validation, log parsing, data extraction — these tasks use the same patterns every developer reaches for. The patterns here have been refined across thousands of production applications.
When to Write Custom Regex
- Your data format is proprietary or domain-specific (custom log formats, legacy file formats)
- You need to extract very specific sub-patterns with capture groups in precise positions
- Performance is critical and you need to optimize the regex engine's backtracking behavior
- You're handling international formats that require locale-aware validation
For those cases, start with the generated pattern as a base, then customize it in our Regex Tester. Building on a working pattern is faster than starting from scratch.