What open 'bad domain' lists can I use to filter newsletter subscriptions from typo domains?

Summary

Filtering newsletter subscriptions from typo domains involves a multi-faceted approach, including leveraging lists of disposable email domains from GitHub and darkmail.domains, utilizing real-time email validation services from Kickbox, Mailgun, Hunter.io, Zerobounce, Bouncer, Neverbounce, and Email Hippo. Also custom scripts for real-time typo correction, and blocking based on MX record lookups. It emphasizes list hygiene practices, proactive domain monitoring, and DNS validation to maintain email deliverability and sender reputation.

Key findings

  • Disposable Domain Lists: GitHub and Darkmail.domains provide lists for identifying disposable and bad domains.
  • Email Validation Services: Services like Kickbox, Mailgun, Hunter.io, Zerobounce, Bouncer, Neverbounce and Email Hippo can detect invalid or risky emails.
  • Real-time Correction Scripts: Custom scripts can provide real-time suggestions to correct typos.
  • MX Record Blocking: Blocking IPs from MX record lookups is an option.
  • List Hygiene and Monitoring: Maintaining list hygiene and proactively monitoring for domain variations can mitigate typo-squatting risks.

Key considerations

  • Suggest Corrections: Provide real-time suggestions for typo corrections on forms.
  • COI/DOI: Always use confirmed opt-in (COI) or double opt-in (DOI).
  • Proactive Monitoring: Continuously monitor for new domain registrations and typo squatting.
  • Combine Strategies: Use a combination of methods including lists, verification services and custom scripts.
  • Regular List Maintenance: Clean email lists and remove disengaged users for better deliverability.

What email marketers say
11Marketer opinions

Several resources and methods can be used to filter newsletter subscriptions from typo domains. These include using lists of disposable email domains from GitHub, utilizing combined lists of bad emails and domains, and employing real-time email validation services that detect typos. Custom scripts and regular expressions can also be implemented. It's recommended to suggest corrections to users in real-time and to manually review suspicious sign-ups.

Key opinions

  • Disposable Domain Lists: GitHub provides comprehensive and actively maintained lists of disposable email domains for filtering out temporary addresses.
  • Combined Bad Domain Lists: Resources like darkmail.domains offer combined lists of bad emails and domains from various sources.
  • Real-Time Validation: Email validation services from Zerobounce, Bouncer, Neverbounce, and Email Hippo offer typo domain filtering and disposable email detection as part of their services.
  • Custom Scripts: Implementing custom scripts using regular expressions can help identify and correct common typos in domain names.

Key considerations

  • Suggest Corrections: Implement real-time suggestions for correcting typo domains on the form.
  • Manual Review: Supplement automated filtering with manual review of suspicious sign-ups.
  • COI/DOI: Always use confirmed opt-in (COI) or double opt-in (DOI) methods to ensure subscribers are valid and engaged.
  • List Maintenance: Actively maintaining email lists and cleaning out disengaged users.
Marketer view

Email marketer from GitHub shares another extensive list of disposable email domains, offering a reliable resource for identifying and blocking temporary email addresses, contributing to better list hygiene.

June 2024 - GitHub
Marketer view

Email marketer from StackOverflow recommends implementing a custom script that checks for common typos in domain names (e.g., 'gmai.com' instead of 'gmail.com') and suggests corrections to the user in real-time.

November 2024 - StackOverflow
Marketer view

Email marketer from Email Geeks suggests leveraging the resource on the form to suggest the correct domain (Not auto-fixing it) while also always using COI/DOI.

October 2024 - Email Geeks
Marketer view

Email marketer from Neverbounce explains they have a service to block disposable emails from subscribing to your service.

January 2023 - Neverbounce
Marketer view

Email marketer from Zerobounce explains that they offer typo domain filtering as part of their real time email validation service, which can prevent typo domains from subscribing to your service.

December 2024 - Zerobounce
Marketer view

Email marketer from Email Geeks shares that <https://www.darkmail.domains/> is also a good resource as it combines a large list of bad emails / domains from various GH sources.

November 2023 - Email Geeks
Marketer view

Email marketer from GitHub provides a comprehensive list of disposable email domains, useful for filtering out temporary or throwaway email addresses during newsletter subscriptions. This list is actively maintained and updated.

October 2021 - GitHub
Marketer view

Email marketer from Bouncer shares information that they have a disposable email filter as part of their verification tool.

April 2022 - Bouncer
Marketer view

Email marketer from Reddit suggests using a combination of disposable email domain lists and regex patterns to identify and block common typo domains, supplemented by manual review of suspicious sign-ups.

January 2022 - Reddit
Marketer view

Email marketer from darkmail.domains offers a combined list of bad emails and domains from various GitHub sources to filter out.

February 2025 - darkmail.domains
Marketer view

Email marketer from Email Hippo explains that they offer disposable email address (DEA) detection as part of their email validation service, allowing users to identify and filter out temporary or throwaway email addresses.

July 2023 - Email Hippo

What the experts say
4Expert opinions

To filter newsletter subscriptions from typo domains, experts recommend focusing on list hygiene and using email verification services to identify these domains at signup. Blocking mail based on MX record IP lookups can also be effective. Actively monitoring new domain registrations similar to your brand and overall sender reputation are also crucial for mitigating risks associated with typo squatting and maintaining email deliverability.

Key opinions

  • List Hygiene: The primary focus should be on list hygiene, which encompasses practices that ensure the quality and validity of email lists.
  • Email Verification Services: Email verification services can identify typo domains and disposable email addresses at the point of signup.
  • MX Record Blocking: Blocking mail based on the IPs that show up in the MX lookup for the typo domain can be an effective method.
  • Domain Monitoring: Actively monitoring new domain registrations similar to your brand can help mitigate typo squatting risks.

Key considerations

  • Proactive Monitoring: Implement continuous monitoring of new domain registrations to identify potential typo squatting.
  • Sender Reputation: Monitor sender reputation and engagement metrics to identify and remove low-quality subscribers.
  • Email Verification Integration: Integrate email verification services into the signup process to prevent typo domains from subscribing.
  • Comprehensive Approach: Combine multiple strategies, including list hygiene, verification services, and MX record blocking, for a comprehensive approach to filtering typo domains.
Expert view

Expert from Email Geeks suggests blocking any mail to the IPs that show up in the MX lookup for the typo domain.

May 2021 - Email Geeks
Expert view

Expert from Spam Resource (John Levine) explains that while there isn't a single definitive list for typo domains, actively monitoring new domain registrations similar to your brand name and using tools that flag suspicious domain variations can help in mitigating the risk of typo squatting and related email deliverability issues.

November 2022 - Spam Resource
Expert view

Expert from Word to the Wise (Laura Atkins) advocates for robust list hygiene practices, including using email verification services that can identify typo domains and disposable email addresses at the point of signup. She also recommends monitoring sender reputation and engagement metrics to identify and remove low-quality subscribers.

July 2021 - Word to the Wise
Expert view

Expert from Email Geeks shares that the search term for filtering typo domains is “list hygiene” and providers like Kickbox will let you run them at signup time.

January 2024 - Email Geeks

What the documentation says
5Technical articles

Various documentation sources highlight the use of email verification APIs and DNS checks to filter newsletter subscriptions from typo domains. Kickbox, Mailgun, and Hunter.io offer APIs that identify invalid or risky email addresses, including typos and disposable domains, at the point of entry. RFC Editor emphasizes the importance of checking DNS records to validate domain configurations. While primarily focused on spam, Spamhaus blocklists can indirectly help identify suspicious domains.

Key findings

  • Real-Time Email Verification APIs: Services like Kickbox, Mailgun, and Hunter.io provide APIs that can identify invalid and risky email addresses, including typos, in real-time during signup.
  • DNS Record Validation: Checking DNS records (MX, A, etc.) is crucial for ensuring that email domains are properly configured and valid, which helps in identifying fraudulent or typo domains.
  • Spamhaus Blocklists: Spamhaus blocklists, though primarily focused on spam, can indirectly assist in identifying suspicious domains associated with spam operations or disposable email services.

Key considerations

  • API Integration: Integrate email verification APIs into the signup process to automatically identify and prevent subscriptions from typo domains and disposable addresses.
  • DNS Validation Process: Implement a process for validating the DNS records of new subscribers to ensure domain validity.
  • Blocklist Monitoring: Monitor Spamhaus blocklists to identify potentially suspicious domains and prevent subscriptions from those sources.
  • Combined Approach: Employ a multi-layered approach combining API verification, DNS validation, and blocklist monitoring for comprehensive protection against typo domains.
Technical article

Documentation from Spamhaus explains that while primarily focused on spam, Spamhaus blocklists can indirectly help identify suspicious domains, especially those associated with known spam operations or disposable email services.

September 2024 - Spamhaus
Technical article

Documentation from RFC Editor explains the importance of checking DNS records (MX, A, etc.) for email domains to ensure they are properly configured and valid, helping to identify potentially fraudulent or typo domains.

March 2023 - RFC Editor
Technical article

Documentation from Hunter.io shares that their Email Verifier tool checks the validity of email addresses, identifying typos, disposable domains, and other issues that can negatively impact email deliverability and sender reputation.

February 2024 - Hunter.io
Technical article

Documentation from Mailgun explains that Mailgun's Email Validation API can detect and prevent subscriptions from invalid email addresses, including those with common typos and disposable domains, thus improving email list quality.

July 2022 - Mailgun
Technical article

Documentation from Kickbox explains that their real-time email verification API identifies invalid or risky email addresses at the point of entry, preventing subscriptions from typo domains and disposable email addresses, contributing to higher deliverability.

October 2024 - Kickbox