email-validator Documentation

The library performs Unicode normalization to ensure that different but semantically equivalent strings are treated identically. This is critical for internationalized email addresses.

• Domain Normalization: Converts fullwidth/halfwidth characters to ASCII (via IDNA/Punycode) and applies Unicode NFC normalization.
• Local Part Normalization: Applies Unicode NFC normalization and removes unnecessary quotes or backslash-escaping in quoted-string local parts.
• Consistency: The normalized field provides the consistent form you should use for database queries and storage to prevent duplicate accounts caused by different Unicode representations of the same address.

emailinfo = validate_email("me@Ｄｏｍａｉｎ.com")
print(emailinfo.normalized)
print(emailinfo.ascii_email)
# prints "me@domain.com" twice

By default, the library rejects special-use domain names like localhost or test to prevent abuse. In non-production test environments, you can allow these in three ways:

1. Pass test_environment=True to the validate_email call.
2. Set the global variable email_validator.TEST_ENVIRONMENT = True.
3. Manually remove a specific domain from the allowed list: email_validator.SPECIAL_USE_DOMAIN_NAMES.remove("test").

import email_validator
email_validator.SPECIAL_USE_DOMAIN_NAMES.remove("test")

Install the package using pip to add email syntax and deliverability validation to your Python 3.10+ project.

pip install email-validator

To improve performance when validating many email addresses, use caching_resolver to create a dns.resolver.Resolver with an LRU cache. Reuse this resolver instance across multiple calls to validate_email.

from email_validator import validate_email, caching_resolver

resolver = caching_resolver(timeout=10)

while True:
  validate_email(email, dns_resolver=resolver)