Summary
The appearance of email addresses with random numbers preceding the domain is a multifaceted issue arising from sloppy data collection, deliberate user actions, and automated bot activity. These addresses often indicate typo-squatting, attempts to evade spam traps, disposable email usage to protect privacy or bypass subscription requirements, or compromised data from paid traffic vendors. RFC 5322 allows numbers in the local part of the email, but the random format is unusual. To prevent this, experts recommend implementing real-time email validation, CAPTCHA, double opt-in procedures, AI-powered verification, robust data governance, transparency in signup processes, bounce rate monitoring, progressive profiling, avoiding purchased lists, stricter signup validation, secure authentication methods (SPF, DKIM, DMARC, TLS), and regular list cleaning.
Key findings
- Data Collection Issues: Sloppy data collection methods, like scraping or bad database imports, can introduce these addresses.
- User Intention: Users may intentionally use invalid addresses to protect privacy, avoid spam, or bypass subscription requirements.
- Automated Bot Activity: Bots often generate random email formats for automated signups.
- Typo-Squatting & Evasion: Random numbers may be a form of typo-squatting or an attempt to evade spam traps or bots.
- Low-Value Signup Proposition: A high number of these addresses may indicate the signup offer is unappealing, leading to fake data.
- Traffic Vendor Issues: Compromised data or poor traffic from paid vendors might be generating these addresses.
- List Bombing: The email address might be part of a larger 'list bombing' attack.
Key considerations
- Real-Time Email Validation: Implement real-time email validation to catch errors and invalid addresses at signup.
- CAPTCHA Implementation: Utilize CAPTCHA to prevent automated bot signups with fake or invalid emails.
- Double Opt-In: Employ a double opt-in process to confirm user intent and verify the email address.
- AI-Powered Verification: Use AI-powered email verification tools to identify and filter suspicious addresses.
- Data Governance Procedures: Establish and enforce robust data governance procedures for input validation and data quality.
- Signup Transparency: Ensure transparency in the signup process to encourage accurate information.
- Bounce Rate Monitoring: Monitor bounce rates and engagement metrics to identify and remove invalid addresses.
- Progressive Profiling: Collect data gradually to reduce the incentive for users to enter fake information.
- List Cleaning: Remove bad emails and non engaged emails with services. Do this regularly and monitor rates.
- Vendor Due Diligence: Thoroughly vet and monitor traffic vendors to ensure the quality of their leads and data.
- Security Protocols: Implement SPF, DKIM, and DMARC records for improved authentication and deliverability.
What email marketers say
13 marketer opinions
The presence of random numbers before the domain name in email addresses typically indicates invalid, fake, or disposable addresses. These addresses may stem from various sources, including sloppy data collection (scraping or database imports), bot signups, typo-squatting, or intentional attempts to avoid providing genuine contact information. Users may also use fake addresses to bypass subscription requirements, protect privacy, or avoid spam. Techniques to prevent the collection of these types of addresses include real-time email validation, CAPTCHA, double opt-in, AI-powered verification tools, robust data governance procedures, transparent signup processes, monitoring bounce rates, progressive profiling, and avoiding the purchase of email lists.
Key opinions
- Source of Invalid Addresses: Random numbers in email addresses often point to typos, bot activity, fake accounts, or disposable emails.
- Data Collection Issues: Sloppy data collection methods like scraping and database imports can introduce invalid email formats.
- Intentional Avoidance: Users may intentionally use invalid addresses to bypass subscriptions, protect privacy, or avoid spam.
- List Bombing: Someone maliciously signing up email addresses to lists to try and discredit the emails.
Key considerations
- Real-Time Validation: Implement real-time email validation to catch errors and filter out invalid addresses during signup.
- Double Opt-In: Use a double opt-in process to confirm the user's intention and verify the validity of the email address.
- Data Governance: Enforce robust data governance procedures, including input validation and data quality standards.
- Bot Prevention: Use CAPTCHA and other bot prevention techniques to minimize automated signups with invalid addresses.
- List Cleaning: Regularly monitor bounce rates and engagement metrics to identify and remove invalid addresses from your email list.
- Transparency at Signup: Be transparent during the signup process to encourage users to provide accurate information.
- Progressive Profiling: Collect data gradually to reduce the temptation to enter fake information.
- Avoid Purchased Lists: Do not use purchased email lists. Instead focus on organic sign ups.
Marketer view
Email marketer from Email Hippo Blog explains that users accidentally adding numbers may be a form of 'typo-squatting' when filling in web forms. Prevention includes real-time email validation to catch errors as they occur and user education by providing clear examples of correct email format.
1 May 2025 - Email Hippo Blog
Marketer view
Email marketer from Reddit explains it could be a simple typo, a bot creating fake accounts, or someone intentionally trying to avoid giving their real email. They advise implementing a confirmation email to ensure the user provided a valid address and genuinely wants to subscribe.
25 Sep 2023 - Reddit
What the experts say
6 expert opinions
Email addresses with random numbers before the domain often result from typo-squatting, attempts to evade spam traps, or a desire to hide personal information. Bot signups and low-value signup propositions can also contribute. Experts recommend stricter validation, CAPTCHA, email verification tools, double opt-in, robust data governance, and checking traffic vendors to mitigate these issues.
Key opinions
- Typo-squatting/Evasion: Random numbers may be a form of typo-squatting or an attempt to evade spam traps and bots.
- Privacy Concerns: Users may enter random numbers to hide personal addresses and avoid spam.
- Bot Activity: Bots often use random email formats for automated signups.
- Vendor Practices: Paid traffic vendors might be generating fake traffic with invalid emails.
- Poor Value Proposition: A high number of these addresses may indicate the signup offer isn't resonating, leading users to provide fake data.
- Spam Trap Creation: Spam traps are sometimes created by collecting fake email addresses and buying the associated domains.
Key considerations
- Stricter Validation: Implement stricter validation at signup, checking for common typos and invalid formats.
- Email Verification Tools: Use email verification tools to identify and filter out invalid email addresses.
- Double Opt-In: Implement a double opt-in process to confirm the user's intention and verify the email address.
- Robust Data Governance: Establish data governance procedures to ensure only valid formats are accepted.
- Traffic Vendor Audits: Check traffic vendors to ensure they are not generating low-quality traffic with invalid emails.
- Address Spam Traps: Actively avoid or mitigate the effects of spam traps.
- Improve Signup Process: Focus on the signup process to reduce fake emails, and increase perceived value.
Expert view
Expert from Word to the Wise responds that one possible scenario is bot signups. They advise focusing on robust data governance procedures that enforce input validation and data quality standards, ensuring that only email addresses that meet predefined format criteria are accepted during registration.
24 Feb 2025 - Word to the Wise
Expert view
Expert from Spam Resource shares that users enter seemingly random numbers to hide their personal addresses and avoid spam. Using email verification tools or implementing a double-opt in process prevents these invalid emails.
30 May 2022 - Spam Resource
What the documentation says
4 technical articles
Technical documentation suggests that while the 'local-part' of an email address can technically include numbers, the random number pattern before the domain is generally indicative of invalid or manipulated addresses. To combat this, strategies include preventing automated bot signups using CAPTCHA, rate limiting, and honeypots; emphasizing user consent and double opt-in procedures to ensure valid emails; using feedback loops; and implementing modern authentication and security protocols (SPF, DKIM, DMARC, TLS) to improve email verification processes.
Key findings
- Syntax Flexibility: RFC 5322 allows numbers in the local-part of an email address, but the random number before domain format isn't formally defined.
- Bot Prevention Techniques: CAPTCHA, rate limiting, and honeypots deter bots from entering fake email addresses.
- Consent and Opt-In: Double opt-in procedures ensure valid email addresses and user consent.
- Security Protocols: Modern authentication (OAuth 2.0) and security protocols (SPF, DKIM, DMARC, TLS) improve email verification.
Key considerations
- Implement Bot Protection: Use CAPTCHA, rate limiting, and honeypots to prevent automated signups.
- Enforce Double Opt-In: Require users to confirm their email addresses via double opt-in.
- Secure Email Infrastructure: Set up SPF, DKIM, and DMARC records to authenticate emails and improve deliverability.
- Monitor Bounce Rates: Implement feedback loops to automatically remove bad email addresses.
Technical article
Documentation from RFC Editor explains the formal syntax for Internet email addresses. Although it doesn't address the specific case of random numbers, it describes the valid characters and structure allowed in the 'local-part' (before the @ symbol), which can technically include numbers, however the random number before domain is not formally defined.
15 Sep 2022 - RFC Editor
Technical article
Documentation from Microsoft shares that implementing modern authentication methods (like OAuth 2.0), setting up SPF, DKIM, and DMARC records, and using transport layer security (TLS) can improve email security and verification processes, thus preventing the collection of manipulated or fake email addresses.
4 Nov 2024 - Microsoft
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