Email Validation
Email validation is a classic regex challenge. Let's build patterns from simple to comprehensive.
Basic Email Pattern
At minimum, an email has: something@something.something
This catches the basics but misses many valid emails.
Exercises
Handling Dots in Username
Usernames can have dots: first.last@example.com
Subdomains
Domains can have subdomains: user@mail.example.com
Plus Addressing
Some emails support + tags: user+tag@example.com
TLD Validation
Top-level domains are 2-6 characters:
Comprehensive Pattern
Edge Cases
Practice Playground
Build your own email validator:
Real-World Considerations
A truly RFC-compliant email regex is incredibly complex. For practical purposes:
- Simple validation:
\S+@\S+\.\S+catches obvious errors - Moderate validation:
[\w.+-]+@[\w.-]+\.[a-zA-Z]{2,}covers most cases - Best practice: Send a confirmation email - that's the only true validation!
Key Takeaways
- Start simple, add complexity as needed
- Username:
[\w.+-]+ - Domain:
[\w.-]+ - TLD:
[a-zA-Z]{2,} - No regex can validate all RFC-compliant emails perfectly
- Confirmation email is the best validation