Regex Guides & Tutorials
Master regular expressions with our comprehensive guides covering everything from basics to advanced optimization and security best practices.
Featured Guides
Email Validation Regex – Complete Guide (JS, Python, PHP, Java, C#)
Comprehensive multi-language email validation guide with RFC-compliant patterns, security considerations, and production-ready examples.
Security Regex Patterns to Prevent Injection and XSS
Essential regex patterns for input validation, sanitization, and protection against injection attacks and XSS vulnerabilities.
All Guides
Email Validation Regex – Complete Guide (JS, Python, PHP, Java, C#)
Comprehensive multi-language email validation guide with RFC-compliant patterns, security considerations, and production-ready examples.
Security Regex Patterns to Prevent Injection and XSS
Essential regex patterns for input validation, sanitization, and protection against injection attacks and XSS vulnerabilities.
Access Token & API Key Validation with Regex – When to Use and When to Avoid
Learn when regex is appropriate for token validation, security implications, and best practices for API authentication patterns.
Regex for Logs and Monitoring – Parse, Filter, and Alert
Master log parsing with regex patterns for monitoring, alerting, and extracting insights from application and system logs.
Regex Performance and Safety – Avoid Catastrophic Backtracking
Write safe, efficient regex patterns while avoiding performance pitfalls, ReDoS vulnerabilities, and catastrophic backtracking.
Regex Fundamentals for Beginners
Start your regex journey with this comprehensive introduction covering basic syntax, common patterns, and practical examples.
Testing and Debugging Regex Patterns
Master the art of testing regex patterns with comprehensive test cases, debugging techniques, and validation strategies.
Cross-Language Regex Implementation
Learn how to implement regex patterns across different programming languages and understand their unique features.
Quick Tips
Use Non-Capturing Groups
Use (?:...) instead of (...) when you don't need to capture the matched text.
(?:https?|ftp)://\S+Prefer Character Classes
Use [0-9] instead of \d for better cross-platform compatibility.
[0-9]{3}-[0-9]{3}-[0-9]{4}Anchor Your Patterns
Use ^ and $ to ensure the entire string matches your pattern.
^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,}$Be Specific with Quantifiers
Use specific quantifiers like {2,10} instead of + when possible.
^[A-Za-z]{2,50}$Recommended Learning Path
Fundamentals
Learn basic syntax and common patterns
Practice
Apply patterns to real-world problems
Advanced Topics
Master performance and security
Ready to Use Regex Patterns?
Browse our collection of production-ready regex patterns with examples, test cases, and performance metrics.