Email validation is a common requirement for nearly every web application, yet most implementations rely on regular expressions—an approach that's often slower and less accurate than it needs to be. Today, I want to share an alternative method that not only validates emails more efficiently but also checks against disposable domains—all while being faster than traditional regex-based solutions.
The Problem with Regex for Email Validation
Most email validation libraries use regular expressions to check if an email address conforms to RFC standards. While regex is powerful, it has some drawbacks:
- Performance overhead: Complex regex patterns can be slow, especially when validating millions of emails.
- Incomplete RFC compliance: Many regex patterns either over-restrict (blocking valid emails) or under-restrict (allowing invalid formats).
- Lack of additional checks: Regex alone can't verify whether an email domain is disposable or temporary.
A Different Approach: Bitmask Logic and Set Lookups
Instead of relying on regex, we implemented a validation method that:
- Uses bitmask comparisons for character validation (faster than regex matching).
-
Checks RFC compliance by directly validating email structure (length,
@position, dot rules). - Includes disposable domain detection with a preloaded database of 180,000+ known temporary email providers.
- Optionally verifies TLDs against ICANN's official list.
The result? A 13.7% performance improvement over the fastest regex-based validator we tested, while also providing more thorough validation.
How It Works
The validation process follows these steps:
-
Basic structural checks (length,
@position, local/domain part sizes). - Local part validation (alphanumeric + special characters, no invalid dot placements).
- Domain validation (correct label formatting, hyphen rules, TLD length).
- Disposable domain check (instant lookup against a Set of known temporary email domains).
- TLD verification (optional check against ICANN-recognized top-level domains).
Because we avoid regex, the validation logic is both faster and more transparent—you can see exactly which rules are being enforced.
Real-World Performance
In benchmarks against popular email validation libraries, this approach consistently outperformed regex-based solutions:
| Library | Avg. Time per Validation |
|---|---|
| throwaway (this method) | 155.73 ns |
| email-validator | 180.47 ns |
| @shelf/is-valid-email | 404.70 ns |
The difference becomes significant when validating large datasets—for example, processing 1 million emails would take:
- ~156ms with this method
- ~180ms with
email-validator - ~405ms with
@shelf/is-valid-email
Disposable Email Detection
Beyond basic validation, this method includes real-time disposable domain checking. The database is automatically updated weekly by scraping known sources of temporary email providers, ensuring new domains are detected quickly.
If a domain is incorrectly flagged (e.g., a legitimate service is mistakenly marked as disposable), users can contribute fixes by submitting pull requests to an allow list.
Open and Community-Driven
The project is open-source (GPL-3.0 licensed) and encourages community contributions:
- Adding new disposable domains (via automated scrapers or manual submissions).
- Improving validation logic (e.g., better handling of quoted strings or internationalized emails).
- Fixing false positives in the disposable domain list.
Try It Out
If you're looking for a faster, more comprehensive email validation solution, you can test it with:
npm install throwaway-email@latest
Or use the raw domain list directly from the GitHub repository.
Example Usage
import validEmail from 'throwaway-email';
// Basic validation (TLD + disposable check)
validEmail("user@example.com"); // true
validEmail("user@tempmail.com"); // false (disposable)
validEmail("user@invalid.tld"); // false (unknown TLD)
Final Thoughts
Regex isn't always the best tool for the job—sometimes, a more direct approach can yield better performance and accuracy. If you're working on a project that requires robust email validation, consider trying this method and contributing to its improvement.
What do you think? Have you encountered performance issues with regex-based validation before? Let us know your experiences!
Top comments (0)