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How can I validate email signups from unusual or new domains to avoid spam traps?

Summary

Validating email signups from unusual or new domains to avoid spam traps requires a multi-faceted approach, combining technical solutions, strategic processes, and continuous monitoring. One strategy is to implement a system where signups from less common domains undergo double opt-in (DOI). Utilizing email validation services and APIs like Mailgun, NeverBounce, and Hunter.io helps to identify typos, disposable email addresses, catch-all domains, and other risky indicators. These tools provide quality scores and deliverability risk assessments. A build-your-own-reputation system can be implemented to increase checks on unfamiliar domains. Other key practices include employing suppression lists to exclude unsubscribed, bounced, and spam-reported addresses, using honeypots to identify and block bots, and continuously monitoring sender reputation. Typo detection and correction features can also prevent accidental misspellings that lead to deliverability issues. Furthermore, gradually increasing sending volume (email warm-up) helps build a positive reputation, and regular blacklist checks are vital for identifying existing issues. Segmenting lists and tailoring content enhances engagement, reducing the likelihood of being marked as spam.

Key findings

  • Double Opt-In (DOI): DOI implementation for less common domains significantly reduces garbage traps and ensures engaged subscribers.
  • Email Validation Services/APIs: Services and APIs from Mailgun, NeverBounce, Hunter.io, etc., identify typos, disposable addresses, catch-all domains, and other risk factors.
  • Build-Your-Own Reputation System: Increase checks on unfamiliar domains to proactively manage list quality.
  • Suppression Lists: Suppression lists automatically exclude unsubscribed, bounced, and spam-reported addresses, protecting sender reputation.
  • Honeypots: Honeypots on signup forms effectively identify and block bots and malicious users.
  • Typo Detection & Correction: Features prevent accidental misspellings, ensuring valid email addresses are collected.
  • Sender Reputation Monitoring: Continuously monitor sender reputation and address deliverability issues promptly.
  • Email Warm-Up: Gradually increasing sending volume establishes a positive reputation.
  • Blacklist Checks: Regularly check IP addresses and domains against blacklists to identify potential issues.
  • List Segmentation: Segment email lists for better targeting to increase engagement.

Key considerations

  • Cost vs. Benefit of COI/DOI: Evaluate the costs and benefits of Confirmed Opt-In/Double Opt-In (COI/DOI), especially for all new signups, balancing increased security with potential friction for legitimate users.
  • Special Handling of Catch-All Domains: Develop a clear strategy for handling identified catch-all domains, which may involve additional verification steps or adjusted sending practices.
  • Integration of Multiple Tools: Effectively integrate various verification tools and services into your signup process for comprehensive validation.
  • Proactive vs. Reactive Measures: Balance proactive measures (e.g., DOI, honeypots) with reactive measures (e.g., suppression lists, blacklist monitoring) for a holistic approach.
  • Building a Reputation: Balance using third-party validation against the work to build-your-own reputation.

What email marketers say

12 marketer opinions

Validating email signups from unusual or new domains to avoid spam traps involves a multi-faceted approach. Several methods exist to ensure the quality of email lists and sender reputation. Real-time email verification services can identify invalid or risky email addresses during signup, including typo detection, disposable emails, and domain issues. Implementing double opt-in (DOI) ensures that only engaged users are added to the list, preventing spam traps and improving deliverability. A build-your-own-reputation system, coupled with AI-powered email scoring and list hygiene techniques such as suppression lists, can further refine email list quality. Other important considerations are segmenting lists for better targeting and engagement, monitoring sender reputation, email warm-up, and checking blacklists. Finally, typo detection tools can help reduce accidental entries.

Key opinions

  • Real-time verification: Using real-time email verification identifies invalid or risky addresses during signup.
  • Double Opt-In: Implementing DOI ensures engaged users and prevents spam traps.
  • AI scoring: AI-powered email scoring assesses the risk level of email addresses.
  • Typo detection: Employing typo detection corrects misspelled domains during signup.
  • List Segmentation: Segmenting email lists increases engagement and relevance.
  • Reputation Monitoring: Monitoring sender reputation helps identify deliverability issues early.
  • Email Warm-up: Gradually increasing sending volume establishes positive sender reputation.
  • Blacklist Checks: Checking IP addresses and domains against blacklists identifies reputation issues.

Key considerations

  • Build Reputation Systems: Building your own reputation system may offer more tailored control.
  • List Hygiene: Employ various list hygiene techniques, including email verification and suppression lists, in combination.
  • COI Value: Consider the value of COI (Confirmed Opt-In) for addressing various delivery issues.

Marketer view

Email marketer from Mailjet advises gradually increasing sending volume from new domains or IPs (email warm-up) to establish a positive sender reputation with ISPs and prevent deliverability issues.

28 Aug 2022 - Mailjet

Marketer view

Email marketer from Email Hippo shares that their service includes typo detection, suggesting alternatives to misspelled domains during signup. This helps prevent users from accidentally entering incorrect email addresses that may lead to spam traps.

6 May 2025 - Email Hippo

What the experts say

4 expert opinions

Validating email signups from unusual or new domains can be achieved using a combination of strategies. Implementing a system where signups from less common domains go through a double opt-in process can reduce garbage traps. Email verification tools can identify catch-all domains, allowing for special handling. Email validation services are also recommended for cleaning email lists and reducing the risk of sending to spam traps. Additionally, using honeypots on signup forms can help identify and block bots and malicious users.

Key opinions

  • Double Opt-In for Uncommon Domains: Implementing double opt-in for signups from less common domains reduces garbage traps.
  • Catch-All Domain Identification: Verification tools can identify catch-all domains for special handling.
  • Email Validation Services: Using email validation services cleans email lists and reduces spam trap risks.
  • Honeypots for Bot Detection: Honeypots identify and block bots and malicious users on signup forms.

Key considerations

  • Special Handling: Determine how to handle catch-all domains once identified (e.g., additional verification steps).
  • COI/DOI burden: Weigh the costs and benefits of COI/DOI especially for all new signups

Expert view

Expert from Word to the Wise explains that using honey pots (email addresses specifically created to catch spammers) on signup forms can help identify and block bots and malicious users, reducing the risk of adding spam traps to your list.

20 Jun 2023 - Word to the Wise

Expert view

Expert from Email Geeks explains that most verification tools are smart enough to denote a catch all domain and warn you about it, so then you can decide if you want to special case it.

21 Mar 2022 - Email Geeks

What the documentation says

5 technical articles

Validating email signups involves using various tools and services to identify and remove potentially harmful email addresses. Email Validation APIs can detect typos, disposable addresses, and spam traps, providing quality scores and deliverability risk assessments. Services also identify catch-all domains, suggesting caution and additional verification steps. Email verification tools check for valid email addresses without sending emails, identifying invalid, disposable, or risky addresses. Suppression lists automatically exclude unsubscribed, bounced, and spam-reported addresses, protecting sender reputation. Amazon SES provides tools for verifying addresses, identifying hard bounces, and managing spam complaints.

Key findings

  • Email Validation APIs: APIs identify typos, disposable addresses, and spam traps.
  • Catch-all Domain Detection: Services identify catch-all domains, which require caution.
  • Email Verification Tools: Tools check for valid addresses without sending emails.
  • Suppression Lists: Suppression lists exclude unsubscribed, bounced, and spam-reported addresses.
  • SES Verification: Amazon SES offers address verification and spam complaint management.

Key considerations

  • Risk Assessment: Understand the deliverability risks associated with catch-all domains.
  • Actionable Steps: Implement additional verification steps for addresses flagged as risky.
  • Tool Integration: Consider how to integrate different verification tools and services into your signup process.

Technical article

Documentation from Hunter.io shares that their email verification tool checks whether an email address exists without sending an actual email. It identifies invalid, disposable, or risky email addresses, improving deliverability rates.

26 Sep 2022 - Hunter.io

Technical article

Documentation from AWS explains that Amazon SES (Simple Email Service) provides tools to verify email addresses before sending. This includes identifying hard bounces and spam complaints to maintain a clean sending reputation.

18 Feb 2022 - AWS

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