Non-human interaction (NHI) during email signup and confirmation poses a significant challenge for marketers and deliverability professionals. These interactions, often driven by automated bots or security scanners, can inflate list sizes with invalid contacts, skew engagement metrics, and potentially lead to deliverability issues. For companies relying on confirmed opt-in (COI) to meet legal or compliance requirements, distinguishing between genuine human engagement and NHI is crucial, especially when local laws may not explicitly define what constitutes a valid COI click in this context. While completely eliminating NHI is likely an unrealistic goal, implementing robust preventative measures at the signup and confirmation stages can significantly reduce its impact.
Key findings
Legal ambiguity: No country's laws explicitly codify what constitutes a confirmed opt-in in the context of non-human interactions, making legal interpretation challenging for businesses operating globally. Businesses should consult their legal counsel for specific guidance. Jakub Olexa on NHI explores automated systems and privacy protection.
Impact on deliverability: NHI can negatively affect email deliverability by introducing fake addresses, leading to higher bounce rates, lower engagement, and potentially getting your domain or IP on a blocklist. For more information, read about how bot signups impact email deliverability.
Multi-layered defense: A combination of technical and strategic measures is most effective. This includes front-end protections on signup forms, checks during the confirmation process, and ongoing list hygiene.
Key considerations
Prioritize user experience: While securing signup forms, ensure that the measures don't unduly hinder legitimate users. Overly aggressive captchas or complex processes can deter genuine signups.
Continuous monitoring: NHI tactics evolve, so regularly review and update your anti-bot strategies. Monitoring engagement metrics and complaint rates can signal potential NHI issues.
Backend validation: Implement server-side checks in addition to client-side measures. This can include rate limiting, IP reputation checks, and analyzing submission patterns. Learn more about backend validations for email opt-in.
Adaptation: The threat landscape is dynamic. Be prepared to adapt your defenses against new bot techniques and privacy-focused technologies like Apple Private Relay, which can obscure IP addresses.
What email marketers say
Email marketers often find themselves on the front lines of defense against non-human interactions during signup. Their experiences highlight practical, iterative approaches to mitigate these challenges, balancing security with the need for a smooth user experience. Many acknowledge that completely eliminating NHI is an unrealistic expectation, necessitating a focus on harm reduction and maintaining list quality.
Key opinions
Layered security: Multiple layers of defense, including captchas, IP reputation checks, and JavaScript requirements, are essential for effective bot prevention. For more on this, consider our guide on preventing nefarious email signups.
Double opt-in as a baseline: While not foolproof against all NHI, double opt-in (COI) remains a critical step in verifying user intent and is often supplemented with other checks.
Realism about NHI: It is generally accepted that completely avoiding all non-human interactions is unrealistic; the goal is to minimize their negative impact and prevent fraud.
Third-party tools: Integrating with third-party verification or fraud prevention services can significantly enhance a marketer's ability to identify and block suspicious signups.
Key considerations
IP blocklist checks: Declining signups from IPs listed on major blacklists, such as Spamhaus, can effectively deter many bot attempts. Consider using our blocklist checker to monitor your own domain.
JavaScript requirements: Requiring JavaScript to be enabled for confirmation clicks or form submissions can block simpler bot scripts.
Alternative verification: While email is preferred, considering multi-factor authentication (MFA) codes delivered via SMS or push notifications can offer an additional layer of security.
Hidden fields (honeypots): Adding invisible fields to signup forms that only bots would fill out can effectively trap and block automated submissions. SMTP.com's blog also discusses protecting sign-up forms from spambots.
Marketer view
An email marketer from Email Geeks suggests exploring alternative channels like SMS or push notifications for verifying opt-in, though they prefer to keep email opt-in within the email ecosystem for consistency.
10 Sep 2024 - Email Geeks
Marketer view
An email marketer from Email Geeks explains they decline signups from IP addresses listed on Spamhaus, finding this an effective method to stop most bot signup attempts from the outset.
10 Sep 2024 - Email Geeks
What the experts say
Industry experts provide a more technical and strategic perspective on combating non-human interaction. They often emphasize the limitations of relying solely on standard methods and highlight the importance of sophisticated detection and mitigation technologies. Their insights underscore the complexity of identifying NHI, especially as automated systems become more advanced.
Key opinions
Advanced bot detection: While basic captchas help, enterprise-grade bot mitigation platforms offer more intricate detection capabilities by analyzing behavioral patterns rather than just simple input. This is crucial for preventing spam bot signups.
ESP capabilities: Email Service Providers (ESPs) that host signup pages are uniquely positioned to offer superior bot prevention, leveraging data across many clients to identify and block abusive patterns.
Dynamic threat landscape: The list of security scanner IPs or problematic CDN networks is constantly changing, making static blocklists ineffective for long-term NHI prevention. Consistent monitoring and adaptation are key.
Beyond the click: While a confirmation click is standard for COI, additional behavioral signals or multi-factor authentication can provide stronger evidence of human interaction.
Key considerations
Cost vs. protection: Enterprise-level bot mitigation solutions can be expensive, so businesses must weigh the cost against the potential damage from unchecked NHI. For strategies on minimizing bot signups, check our best practices guide.
CDN impact: Be cautious when blocking IP ranges associated with Content Delivery Networks (CDNs), as legitimate services like Apple Private Relay use them, potentially leading to false positives.
Holistic approach: Combating NHI effectively requires a comprehensive strategy that integrates web form protection with email verification and continuous monitoring of subscriber behavior.
Legal interpretation: Given the lack of specific legal definitions for NHI in confirmed opt-in, deferring to legal counsel for local law interpretations is crucial for compliance.
Expert view
An expert from Email Geeks indicates that blocking CDNs based on assumptions of NHI isn't feasible because legitimate services, like Apple Private Relay, utilize them, and a comprehensive list of security scanner IPs is virtually impossible to maintain.
10 Sep 2024 - Email Geeks
Expert view
An expert from Email Geeks suggests that Email Service Providers (ESPs) that host signup pages are better equipped to handle bot mitigation because they observe greater traffic across all their clients. This allows them to develop robust reputation points and integrate with fraud prevention tools more effectively.
10 Sep 2024 - Email Geeks
What the documentation says
Documentation from cybersecurity and identity management companies sheds light on the broader context of non-human identities (NHIs) and their security implications. While much of this documentation focuses on enterprise-level identity management, the principles of detection, verification, and access control are highly relevant to preventing NHI during email signup and confirmation. It emphasizes that NHIs are pervasive and require dedicated strategies.
Key findings
NHI prevalence: Non-human identities (NHIs) are a significant and growing component of digital traffic, often outnumbering human identities in many online environments.
Security implications: NHIs are used by non-human actors to access resources, move data, and run automated tasks, including malicious activities like fraudulent signups and subscription bombing. For prevention strategies, see our guide on protecting email list signup forms from bots.
Identity verification core: The primary purpose of identity verification is to enhance security, prevent identity fraud, and comply with regulatory requirements, which extends to validating email signups.
Key considerations
Behavioral analysis: Modern bot detection relies on analyzing user behavior patterns rather than simple static checks to identify non-human activities, ensuring more accurate detection.
Comprehensive security: Securing web forms and email processes requires a comprehensive security framework that integrates with broader identity and access management (IAM) strategies.
Proactive defense: It is critical to implement preventive measures for securing signup forms proactively, rather than reacting to bot attacks after they occur. This includes using methods for preventing bot sign-ups and suspicious contacts.
Technical article
Documentation from Delinea emphasizes that non-human identities (NHIs) are distinct from human identities and are crucial for automated systems accessing resources or moving data, highlighting the need for specialized management and protection.
20 May 2024 - Delinea.com
Technical article
Omdia's documentation on the Fundamentals of Non-Human Identities identifies key trends and challenges in securing NHIs, outlining essential capabilities for products designed to manage these identities effectively across an enterprise.