How do I validate extracted email addresses?
Validating extracted email addresses ensures you only keep legitimate contacts and avoid spam traps or malformed data.
1. Format validation:
Basic validation checks the format using regex patterns that verify standard email structure: username@domain.tld.
However, format validation alone isn't sufficient - an email can be correctly formatted but still be invalid.
2. Domain validation:
Perform DNS lookups to verify the domain has valid MX (Mail Exchange) records, indicating it can receive emails.
Libraries that help:
email-validator(Python)validator.js(JavaScript)
3. SMTP verification (advanced):
Connect to the mail server and check if the specific email address exists without actually sending a message.
Important note: Many mail servers now reject this type of verification to prevent harvesting.
4. Deduplication and normalization:
- Remove exact duplicates
- Convert to lowercase for consistency
- Trim whitespace
5. Filter invalid patterns:
Filter out obvious invalid patterns like:
example@example.comtest@test.com- Addresses from placeholder domains
- Disposable email addresses
6. Third-party verification services:
For lead generation purposes, consider using third-party email verification services that maintain databases of:
- Known invalid addresses
- Disposable email domains
- Spam-trap addresses
- Bounced emails
Best practices:
- Validate format first (fastest)
- Check DNS/MX records for important emails
- Use verification services for bulk contact lists
- Maintain your own list of invalid patterns based on your data